PANDA Phase One
G. Barucca, ..., G. Korcyl, R. Lalik, A. Malige, P. Moskal , K. Nowakowski , W. Przygoda , N. Rathod , P. Salabura , J. Smyrski , et al.
abstract
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future antiProton ANnihilations at DArmstadt (PANDA or P(anti)P PANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in the non-perturbative regime remains one of the greatest challenges in contemporary physics. The antiproton-nucleon interaction studied with PANDA provides crucial tests in this area. Furthermore, the high-intensity, low-energy domain of PANDA allows for searches for physics beyond the Standard Model, e.g. through high precision symmetry tests. This paper takes into account a staged approach for the detector setup and for the delivered luminosity from the accelerator. The available detector setup at the time of the delivery of the first antiproton beams in the HESR storage ring is referred to as the Phase One setup.The physics programme that is achievable during Phase One is outlined in this paper.
The potential of Lambda and Xi- studies with PANDA at FAIR
G. Barucca, F. Davi, G. Lancioni, P. Mengucci, L. Montalto, P. P. Natali, N. Paone, D. Rinaldi, L. Scalise, W. Erni, B. Krusche, M. Steinacher, N. Walford, N. Cao, Z. Liu, C. Liu, B. Liu, X. Shen, S. Sun, J. Tao, X. A. Xiong, G. Zhao, J. Zhao, M. Albrecht, W. Alkakhi, S. Bökelmann, F. Feldbauer, M. Fink, J. Frech, V. Freudenreich, M. Fritsch, R. Hagdorn, F. H. Heinsius, T. Held, T. Holtmann, I. Keshk, H. Koch, B. Kopf, M. Kuhlmann, M. Kümmel, M. Küßner, J. Li, A. Mustafa, M. Pelizäus, A. Pitka, J. Reher, G. Reicherz, M. Richter, C. Schnier, L. Sohl, M. Steinke, T. Triffterer, C. Wenzel, U. Wiedner, H. Denizli, N. Er, R. Beck, C. Hammann, J. Hartmann, B. Ketzer, J. Müllers, M. Rossbach, B. Salisbury, C. Schmidt, U. Thoma, M. Urban, A. Bianconi, M. Bragadireanu, D. Pantea, M. Domagala, G. Filo, E. Lisowski, F. Lisowski, M. Michałek, P. Poznański, J. Płażek, K. Korcyl, A. Kozela, P. Lebiedowicz, K. Pysz, W. Schäfer, A. Szczurek, T. Fiutowski, M. Idzik, K. Swientek, P. Terlecki, G. Korcyl, R. Lalik, A. Malige, P. Moskal, K. Nowakowski, W. Przygoda, N. Rathod, Z. Rudy, P. Salabura, J. Smyrski, I. Augustin, R. Böhm, I. Lehmann, L. Schmitt, V. Varentsov, M. Al-Turany, A. Belias, H. Deppe, R. Dzhygadlo, H. Flemming, A. Gerhardt, K. Götzen, A. Heinz, P. Jiang, R. Karabowicz, S. Koch, U. Kurilla, D. Lehmann, J. Lühning, U. Lynen, H. Orth, K. Peters, J. Rieger, T. Saito, G. Schepers, C. J. Schmidt, C. Schwarz, J. Schwiening, A. Täschner, M. Traxler, B. Voss, P. Wieczorek, V. Abazov, G. Alexeev, V. A. Arefiev, V. Astakhov, M. Yu. Barabanov, B. V. Batyunya, V. Kh. Dodokhov, A. Efremov, A. Fechtchenko, A. Galoyan, G. Golovanov, E. K. Koshurnikov, Y. Yu. Lobanov, A. G. Olshevskiy, A. A. Piskun, A. Samartsev, S. Shimanski, N. B. Skachkov, A. N. Skachkova, E. A. Strokovsky, V. Tokmenin, V. Uzhinsky, A. Verkheev, A. Vodopianov, N. I. Zhuravlev, D. Branford, D. Watts, M. Böhm, W. Eyrich, A. Lehmann, D. Miehling, M. Pfaffinger, N. Quin, L. Robison, K. Seth, T. Xiao, D. Bettoni, A. Ali, A. Hamdi, M. Himmelreich, M. Krebs, S. Nakh
abstract
he antiproton experiment PANDA at FAIR is designed to bring hadron physics to a new level in terms of scope, precision and accuracy. In this work, its unique capability for studies of hyperons is outlined. We discuss ground-state hyperons as diagnostic tools to study non-perturbative aspects of the strong interaction, and fundamental symmetries. New simulation studies have been carried out for two benchmark hyperon-antihyperon production channels: p(anti)p -> Lambda(anti)Lambda and p(anti)p -> anti(Xi)+Xi-. The results, presented in detail in this paper, show that hyperon-antihyperon pairs from these reactions can be exclusively reconstructed with high efficiency and very low background contamination. In addition, the polarisation and spin correlations have been studied, exploiting the weak, self-analysing decay of hyperons and antihyperons. Two independent approaches to the finite efficiency have been applied and evaluated: one standard multidimensional efficiency correction approach, and one efficiency independent approach. The applicability of the latter was thoroughly evaluated for all channels, beam momenta and observables. The standard method yields good results in all cases, and shows that spin observables can be studied with high precision and accuracy already in the first phase of data taking with PANDA.
Directed, elliptic and higher order flow harmonics of protons, deuterons and tritons in Au+Au collisions at sqrt(s_NN) = 2.4 GeV
J. Adamczewski-Musch, ...., G. Korcyl, ...., R. Lalik, ..., A. Malige, ...K. Nowakowski,...., W. Przygoda,...K. Pysz, ..., N. Rathod, ...,P. Salabura, .., U. Singh, J. Smyrski, et al
abstract
Flow coefficients vn of the orders n = 1 - 6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons and tritons as a function of centrality, transverse momentum and rapidity in Au+Au collisions at sqrt(s_NN) = 2.4 GeV. Combining the information from the flow coefficients of all orders allows to construct for the first time, at collision energies of a few GeV, a complete, multi-differential picture of the emission pattern of these particles. The ratio v4/v22 at mid-rapidity is found to be remarkably close to the value 0.5, as might be indicative for an ideal fluid scenario.
Study of the space charge effect in straw tube detectors for the PANDA experiment
N. Rathod, J. Smyrski, A. Malige
abstract
The straw tube detectors in the PANDA experiment will work in high particle fluxes reaching up to 25 kHz/cm(2). We performed measurement of the gas gain drop in the PANDA straws due to the space charge effect expected at the high particle fluxes. The applied experimental method and obtained results are presented and are compared with calculations of the gas gain drop based on known mobility of positive ions.
Isotensor Dibaryon in the pp -> pp pi(+)pi(-) Reaction?
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, W. Parol, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, V. Serdyuk, B. Shwartz, T. Skorodko, M. Skurzok, J. Smyrski, et al.
abstract
Exclusive measurements of the quasifree pp -> pp pi(+)pi(-) reaction have been carried out at WASA@ COSY by means of pd collisions at T-p = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region T-p = 1.08-1.36 GeV, which is the region of N* (1440) and Delta(123)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor Delta N dibaryon resonance with I(J(P)) = 2(1(+)) produced associatedly with a pion is able to overcome these deficiencies.
Pressure stabilized straw tube modules for the PANDA Forward Tracker
J. Smyrski, T. Fiutowski, P. Gianotti, A. Heczko, M. Idzik, M. Kajetanowicz, G. Korcyl, B. Korzeniak, R. Lalik, E. Lisowski, A. Malarz, W. Migdal, A. Misiak, W. Przygoda, J. Ritman, P. Salabura, M. Savrie, K. Swientek, P. Wintz, A. Wronska
abstract
The design of straw tube detector modules developed for the PANDA Forward Tracker is presented. One module consists of 32 straws with 10 mm diameter, arranged in two staggered layers, and has a very low material budget of only 8.8.10(-4 )X(0). The overpressure of the working gas mixture of 1 bar makes the module self-supporting and enables the use of lightweight and compact support frames. Detection planes in the Forward Tracker consist of modules mounted closely, without gaps, next to each other on a support frame. A module can be mounted and dismounted from the frame without the need to remove the neighboring modules, enabling fast repairs. Technical details of the detector design and the assembly procedure of the straw tubes and the straw modules as well as results of performed tests of the modules are given.
Readout Electronics and Data Acquisition for Gaseous Tracking Detectors
G. Korcyl, P. Strzempek, A. Apostolou, T. Fiutowski, M. Idzik, M. Kajetanowicz, D. Przyborowski, P. Salabura, J. Smyrski, K. Swientek, P. Wintz
abstract
A complete, general solution for collecting and processing data from gaseous tracking detectors in high-rate applications has been developed. The readout chain consists of front-end modules equipped with PASTTREC ASIC chips and trigger readout boards version 3 (TRBv3) as a readout platform. The platform is accompanied by dedicated control, monitoring, and data quality assessment software. The entire system has been evaluated with a tracking system based on straw detectors in laboratory and in-beam experiments. In this paper, we present key elements of the system as well as results of various tests. The measured PASTTREC operation characteristics and the TRBv3 specification used for the readout allow us to adapt and to integrate it to the existing HADES spectrometer and the PANDA detector, an experiment under construction, both located at the FAIR facility in Darmstadt.
Multichannel FPGA based MVT system for high precision time (20 ps RMS) and charge measurement
M. Palka, P. Strzempek, G. Korcyl, T. Bednarski, S. Niedzwiecki, P. Bialas, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Jasinska, D. Kaminska, M. Kajetanowicz, P. Kowalski, T. Kozik, W. Krzemien, E. Kubicz, M. Mohhamed, L. Raczynski, Z. Rudy, O. Rundel, P. Salabura, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki, M. Zielinski, B. Zgardzinska, P. Moskal
abstract
In this article it is presented an FPGA based Multi-Voltage Threshold (MVT) system which allows of sampling fast signals (1-2 ns rising and falling edge) in both voltage and time domain. It is possible to achieve a precision of time measurement of 20 ps RMS and reconstruct charge of signals, using a simple approach, with deviation from real value smaller than 10%. Utilization of the differential inputs of an FPGA chip as comparators together with an implementation of a TDC inside an FPGA allowed us to achieve a compact multi-channel system characterized by low power consumption and low production costs. This paper describes realization and functioning of the system comprising 192-channel TDC board and a four mezzanine cards which split incoming signals and discriminate them. The boards have been used to validate a newly developed Time-of-Flight Positron Emission Tomography system based on plastic scintillators. The achieved full system time resolution of sigma (TOF) approximate to 68 ps is by factor of two better with respect to the current TOF-PET systems.
Design of the forward straw tube tracker for the PANDA experiment
J. Smyrski, A. Apostolou, J. Biernat, W. Czyzycki, G. Filo, E. Fioravanti, T. Fiutowski, P. Gianotti, M. Idzik, G. Korcyl, K. Korcyl, E. Lisowski, F. Lisowski, J. Plazek, D. Przyborowski, W. Przygoda, J. Ritman, P. Salabura, M. Savrie, P. Strzempek, K. Swientek, P. Wintz, A. Wronska
abstract
The design of the Forward Tracker for the Forward Spectrometer of the PANDA experiment is described. The tracker consists of 6 tracking stations, each comprising 4 planar double layers of straw tube detectors, and has a total material budget of only 2% X-0. The straws are made self-supporting by a 1 bar over-pressure of the working gas mixture (Ar/CO2). This allows to use lightweight and compact rectangular support frames for the double layers and to split the frames into pairs of C-shaped half-frames for an easier installation on the beam line.
Calculation of the time resolution of the J-PET tomograph using kernel density estimation
L. Raczyński, W. Wiślicki, W. Krzemień, P. Kowalski, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, D. Kamińska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, Z. Rudy, O. Rundel, N. Gupta-Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, B. Zgardzińska, M. Zieliński and P. Moskal
abstract
In this paper we estimate the time resolution of the J-PET scanner built from plastic scintillators. We incorporate the method of signal processing using the Tikhonov regularization framework and the kernel density estimation method. We obtain simple, closed-form analytical formulae for time resolution. The proposed method is validated using signals registered by means of the single detection unit of the J-PET tomograph built from a 30?cm long plastic scintillator strip. It is shown that the experimental and theoretical results obtained for the J-PET scanner equipped with vacuum tube photomultipliers are consistent.
Measurement of gamma quantum interaction point in plastic scintillator with WLS strips
J. Smyrski, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, N. Gupta-Sharma, M. Gorgol, B. Jasińska, M. Kajetanowicz, D. Kamińska, G. Korcyl, P. Kowalski, W. Krzemień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, P. Salabura, M. Silarski, A. Strzelecki, A. Wieczorek, W. Wiślicki, J. Wojnarska, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
The feasibility of measuring the aśxial coordinate of a gamma quantum interaction point in a plastic scintillator
bar via the detection of scintillation photons escaping from the scintillator with an array of wavelength-shifting
(WLS) strips is demonstrated. Using a test set-up comprising a BC-420 scintillator bar and an array of sixteen
BC-482A WLS strips we achieved a spatial resolution of 5 mm (?) for annihilation photons from a 22Na isotope.
The studied method can be used to improve the spatial resolution of a plastic-scintillator-based PET scanner
which is being developed by the J-PET collaboration.
Measurement of polarization observables of the associated strangeness production in proton proton interactions
F. Hauenstein, E. Borodina, H. Clement, E. Doroshkevich, R. Dzhygadlo, K. Ehrhardt, W. Eyrich, W. Gast, A. Gillitzer, D. Grzonka, S. Jowzaee, P. Klaja, L. Kober, K. Kilian, M. Krapp, M. Mertens, P. Moskal, J. Ritman, E. Roderburg, M. Roder, W. Schroeder, T. Sefzick, J. Smyrski, P. Wintz, P. Wustner
abstract
The Lambda polarization, the analyzing power, and the Lambda spin transfer coefficient of the reaction pp -> pK(+) Lambda were measured at beam momenta of 2.70 GeV/c and 2.95 GeV/c corresponding to excess energies of 122MeV and 204MeV. While the analyzing power and the spin transfer coefficient do not change significantly with the excess energy, the Lambda polarization varies strongly and changes its sign. As this is the first measurement of polarization observables below an excess energy of 200MeV, the change of the sign of the Lambda polarization was not observed before. The high statistics of the data (approximate to 200 k events for each momentum) enables detailed studies of the dependence of the Lambda polarization and the analyzing power on the center-of-mass momentum of the particles. The results of the spin transfer coefficient are in qualitative agreement with the DISTO experiment. The Lambda polarization data of 2.95 GeV/c are only conform with the DISTO experiment, while both the 2.70 GeV/c and 2.95 GeV/c data differ strongly from all previous measurements, whether exclusive or inclusive.
Experimental study of the pd (dp) -> He-3 pi pi reactions close to threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, R. Joosten, K. Kilian, A. Kozela, H. Machner, A. Magiera, J. Munkel, P. von Neumann-Cosel, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, R. Tolle, C. Wilkin
abstract
New experimental data on the pd -> He-3 pi(+)pi(-) reaction obtained with the COSY-MOMO detector below the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam and the higher counting rates achieved were especially important at low excess energies. The comparison of these data with inclusive pd -> He-3 X-0 rates allowed estimates also to be made of pi(0)pi(0) production. The results confirm our earlier findings that, close to threshold, there is no enhancement at low excitation energies in the pi(+)pi(-) system, where the data seem largely suppressed compared with phase space. Possible explanations for this behavior, such as strong p waves in the pi(+)pi(-) system or the influence of two-step processes, are explored.
Development of a dedicated front-end electronics for straw tube trackers in the (P)over-barANDA experiment
D. Przyborowski, T. Fiutowski, M. Idzik, M. Kajetanowicz, G. Korcyl, P. Salabura, J. Smyrski, P. Strzempek, K. Swientek, P. Terlecki, J. Tokarz
abstract
The design and tests of front-end electronics for straw tube trackers in the PANDA experiment at FAIR are presented. The challenges for the front-end electronics, comprising operation at high counting rate up to 1MHz per straw tube, are discussed and the proposed architecture comprising a switched gain charge sensitive preamplifier (CSP), a pole-zero cancellation circuit (PZC), a second order variable peaking time shaper, a trimming ion tail cancellation circuit, and a baseline holder (BLH), is described. The front-end provides an analogue output and a discriminator with LVDS differential driver for the Time-of-Arrival (ToA) and Time-over-Threshold (ToT) measurements. A prototype readout ASIC featuring four channels was fabricated in 0.35 mu m CMOS technology consuming 15.5 mW (analog part) and 12 mW (LVDS) per channel. The results of measurements of peaking time (25-67 ns), gain, noise (ENC 800-2500 el. for various gains), time walk and jitter are presented as well as the first results obtained with prototype straw tubes connected.
Application of the compress sensing theory for improvement of the TOF resolution in a novel J-PET instrument
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, N. Gupta-Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
High-precision measurement of the associated strangeness production in proton-proton interactions
S. Jowzaee, E. Borodina, H. Clement, E. Doroshkevich, R. Dzhygadlo, K. Ehrhardt, W. Eyrich, W. Gast, A. Gillitzer, D. Grzonka, F. Hauenstein, P. Klaja, L. Kober, K. Kilian, M. Krapp, M. Mertens, P. Moskal, J. Ritman, E. Roderburg, M. Roder, W. Schroeder, T. Sefzick, J. Smyrski, P. Wintz, P. Wustner
abstract
A new high-precision measurement of the reaction at a beam momentum of 2.95 GeV/c with more than 200 000 analyzed events allows a detailed analysis of differential observables and their inter-dependencies. Correlations of the angular distributions with momenta are examined. The invariant mass distributions are compared for different regions in the Dalitz plots. The cusp structure at the threshold is described with the Flatt, formalism and its variation in the Dalitz plot is analyzed.
High precision measurement of the associated strangeness production in proton proton interactions
S. Jowzaee, ..., P. Moskal, ... , J. Smyrski
abstract
A new high precision measurement of the reaction pp N pK ` Lambda at a beam momentum of 2.95 GeV/c with more than 200 000 analyzed events allows a detailed analysis of differential observables and their inter-dependencies. Correlations of the angular distributions with momenta are examined. The invariant mass distributions are compared for different regions in the Dalitz plots. The cusp structure at the NSigma threshold is described with the Flatte formalism and its variation in the Dalitz plot is analyzed.
Near-threshold charged kaon pair production in two protons collisions
D. Gil, J. Smyrski
abstract
The pp -> ppK(+)K(-) reaction was measured near threshold at excess energy Q = 4.5 MeV using the COSY-11 detection system installed at the COSY-Juelich accelerator. Preliminary value of upper limit of the total cross section was determined. This limit indicates that an enhancement of the total cross section close to the threshold, caused by the final state interaction, is smaller than suggested by extrapolation of data measured at higher energies.
Readout Electronics and Data Acquisition for Gaseous Tracking Detectors
M. Idzik, G. Korcyl, D. Przyborowski, P. Salabura, J. Smyrski, P. Strzempek
abstract
A complete solution for collecting and processing data from gaseous tracking detectors has been developed. The readout chain consists of Front-End Modules (FEM) equipped with PASTTREC2 ASIC chips and Trigger Readout Board v3 (TRBv3) as a readout platform, together with control and monitoring mechanisms and data quality assessment software. The entire system has been evaluated in the laboratory as well as in-beam experiments. The results show drift time measurement and Time-over-Threshold time precision measurement below 1 ns and a high counting rate performance per channel. Measured PASTTREC2 operation characteristics as well as the TRBv3 platform used for readout allow to adapt and integrate the system under discussion to the existing HADES spectrometer and the PANDA detector, an experiment under construction, both located at FAIR facility in Darmstadt.
J-PET: A Novel TOF-PFT Detector based on Plastic Scintillators
P. Moskal, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Hiesmayr, B. Jasinska, D. Kaminska, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemien, E. Kubicz, M. Mohammed, M. Pawlik-Niedzwiecka, S. Niedzwiecki, M. Palka, L. Raczynski, Z. Rudy, O. Rundel, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki, B. Zgardzinska, M. Zielinski
abstract
The purpose of the reported research is the elaboration of the method for construction of the cost-effective whole body single-bed positron emission tomography scanner enabling simultaneous PET/CT and PET/MR imaging The Jagiellonian Positron Emission Tomograph (J-PET) is built out of 192 scintillator strips arranged axially in three layers forming a cylindrical diagnostic chamber with the diameter of 85 cm and axial field of-view of 50 cm. The novelty of the concept lies in employing long strips of plastic scintillators instead of crystals as detectors of the annihilation quanta, and in using the timing of signals instead of their amplitudes for the reconstruction of Lines-of Response. To take advantage of the superior timing properties of plastic scintillators a novel multi-voltage-threshold front-end electronics was developed allowing for sampling of signals in a voltage domain. An axial arrangement of long strips of plastic scintillators, and their small light attenuation allows us to make a TOE-PET scanner with a long axial field-of-view. The presented solution opens unique possibilities of combining PET with CT and PET with MRI for scanning the same part of a patient at the same time with both methods. The relative ease of the cost effective increase of the axial field-of-view makes the J-PET tomograph competitive with respect to the current commercial PET scanners as regards sensitivity and time resolution.
Statistical Analysis of Time Resolution of the J-PET Scanner
L. Raczynski, W. Wislicki, P. Kowalski, W. Krzemien, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Hiesmayr, B. Jasinska, D. Kaminska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedzwiecka, S. Niedzwiecki, M. Palka, Z. Rudy, O. Rundel, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, B. Zgardzinska, M. Zielinski, P. Moskal
abstract
The commercial Positron Emission Tomography (PET) scanners use inorganic crystal scintillators for the detection of gamma photons. The Jagiellonian-PET (J-PET) detector exhibits high time resolution due to use of fast plastic scintillators and dedicated electronics circuits. Since the time resolution of PET scanner is influenced by numerous factors, e.g. a type of photomultipliers attached to the scintillators, the optimal selection of components of the J-PET system requires detailed understanding of the method for calculation the time resolution. In this paper we show the idea of this method, based on statistical analysis of the observed signals on the photomultiplier's output. The method is tested using signals registered by means of the single detection module of the J-PET scanner built out from 30 cm long plastic scintillator strips. We investigate two main factors affecting the photon registration probability, photomultipliers quantum efficiency and photomultipliers transit time spread. We demonstrate that the quantum efficiency of photomultipliers represents the most important factor influencing overall performance of the J-PET scanner.
Studies of discrete symmetries in a purely leptonic system using the Jagiellonian Positron Emission Tomograph
P. Moskal, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, N. Gupta-Sharma, M. Gorgol, BC. Hiesmayr, B. Jasinska, D. Kaminska, O. Khreptak, G. Korcyl, P. Kowalski, W. Krzemien, N. Krawczyk, E. Kubicz, M. Mohammed, S. Niedzwiecki, M. Pawlik-Niedzwiecka, L. Raczynski, Z. Rudy, M. Silarski, J. Smyrski, A. Wieczorek, W. Wislicki, B. Zgardzinska, M. Zielinski
abstract
Discrete symmetries such as parity (P), charge-conjugation (C) and time reversal (T) are of fundamental importance in physics and cosmology. Breaking of charge conjugation symmetry (C) and its combination with parity (CP) constitute necessary conditions for the existence of the asymmetry between matter and antimatter in the observed Universe. The presently known sources of discrete symmetries violations can account for only a tiny fraction of the excess of matter over antimatter. So far CP and T symmetries violations were observed only for systems involving quarks and they were never reported for the purely leptonic objects. In this article we describe briefly an experimental proposal for the test of discrete symmetries in the decays of positronium atom which is made exclusively of leptons. The experiments are conducted by means of the Jagiellonian Positron Emission Tomograph (J-PET) which is constructed from strips of plastic scintillators enabling registration of photons from the positronium annihilation. J-PET tomograph together with the positronium target system enable to measure expectation values for the discrete symmetries odd operators constructed from (i)spin vector of the ortho-positronium atom, (ii) momentum vectors of photons originating from the decay of positronium, and (iii) linear polarization direction of annihilation photons. Linearly polarized positronium will be produced in the highly porous aerogel or polymer targets, exploiting longitudinally polarized positrons emitted by the sodium Na-22 isotope. Information about the polarization vector of ortho-positronium will be available on the event by event basis and will be reconstructed from the known position of the positron source and the reconstructed position of the ortho-positronium annihilation. In 2016 the first tests and calibration runs are planned, and the data collection with high statistics will commence in the year 2017.
Multiple Scattering and Accidental Coincidences in the J-PET Detector Simulated Using GATE Package
P. Kowalski, P. Moskal, W. Wislicki, L. Raczynski, T. Bednarski, P. Bialas, J. Bulka, E. Czerwinski, A. Gajos, A. Gruntowski, D. Kaminska, L. Kaplon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemien, E. Kubicz, S. Niedzwiecki, M. Palka, Z. Rudy, P. Salabura, NG. Sharma, M. Silarski, A. Slomski, J. Smyrski, A. Strzelecki, A. Wieczorek, I. Wochlik, M. Zielinski, N. Zon
abstract
Novel positron emission tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta.
A pilot study of the novel J-PET plastic scintillator with 2-(4-styrylphenyl)benzoxazole as a wavelength shifter
A. Wieczorek, P. Moskal, Sz. Niedźwiecki, T. Bednarski, P. Białas, E. Czerwiński, A. Danel, A. Gajos, A. Gruntowski, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, T. Uchacz, W. Wiślicki, M. Zieliński, N. Zoń
abstract
For the first time a molecule of 2-(4-styrylphenyl)benzoxazole containing benzoxazole and stilbene groups is applied as a scintillator dopant acting as a wavelength shifter. In this article a light yield of the plastic scintillator, prepared from styrene doped with 2 wt% of 2,5-diphenylbenzoxazole and 0.03 wt% of 2-(4-styrylphenyl)benzoxazole, is determined to be as large as 60% ? 2% of the anthracene light output. There is a potential to improve this value in the future by the optimization of the additives concentrations.
Compressive sensing of signals generated in plastic scintillators in a novel J-PET instrument
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
The J-PET scanner, which allows for single bed imaging of the whole human body, is currently under development at the Jagiellonian University. The discussed detector offers improvement of the Time of Flight (TOF) resolution due to the use of fast plastic scintillators and dedicated electronics allowing for sampling in the voltage domain of signals with durations of few nanoseconds. In this paper we show that recovery of the whole signal, based on only a few samples, is possible. In order to do that, we incorporate the training signals into the Tikhonov regularization framework and we perform the Principal Component Analysis decomposition, which is well known for its compaction properties. The method yields a simple closed form analytical solution that does not require iterative processing. Moreover, from the Bayes theory the properties of regularized solution, especially its covariance matrix, may be easily derived. This is the key to introduce and prove the formula for calculations of the signal recovery error. In this paper we show that an average recovery error is approximately inversely proportional to the number of acquired samples.
Analysis framework for the J-PET scanner
W. Krzemień, A. Gajos, A. Gruntowski, K. Stola, D. Trybek, T. Bednarski, P. Białas, E. Czerwiński, D. Kamińska, L. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, E. Kubicz, P. Moskal, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, N. Zoń
abstract
J-PET analysis framework is a flexible, lightweight, ROOT-based software package which provides the tools to develop reconstruction and calibration procedures for PET tomography. In this article we present the implementation of the full data-processing chain in the J-PET framework which is used for the data analysis of the J-PET tomography scanner. The Framework incorporates automated handling of PET setup parameters' database as well as high level tools for building data reconstruction procedures. Each of these components is briefly discussed.
Hit time and hit position reconstruction in the J-PET detector based on a library of averaged model signals
P. Moskal, N.G.Sharma, M.Silarski, T. Bednarski, P. Białas, J. Bułka, E. Czerwiński, A. Gajos, D. Kamińska, L. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, I. Wochlik, M. Zieliński, N. Zoń
abstract
n this article we present a novel method of hit time and hit position reconstruction in long scintillator detectors. We take advantage of the fact that for this kind of detectors amplitude and shape of registered signals depends strongly on the position where particle hit the detector. The reconstruction is based on determination of the degree of similarity between measured and averaged signals stored in a library for a set of well-defined positions along the scintillator. Preliminary results of validation of the introduced method with experimental data obtained by means of the double strip prototype of the J-PET detector are presented.
GPU accelerated image reconstruction in a two-strip J-PET tomograph
P. Białas, J. Kowal, A. Strzelecki, T. Bednarski, E. Czerwiński, A. Gajos, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, P. Moskal, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Wieczorek, W. Wiślicki, M. Zieliński, N. Zoń
abstract
We present a fast GPU implementation of the image reconstruction routine, for a novel two strip PET detector that relies solely on the time of flight measurements.
A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals
P. Moskal, N. Zoń, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński
abstract
A novel method of hit time and hit position reconstruction in scintillator detectors is described. The method is based on comparison of detector signals with results stored in a library of synchronized model signals registered for a set of well-defined positions of scintillation points. The hit position is reconstructed as the one corresponding to the signal from the library which is most similar to the measurement signal. The time of the interaction is determined as a relative time between the measured signal and the most similar one in the library. A degree of similarity of measured and model signals is defined as the distance between points representing the measurement- and model-signal in the multi-dimensional measurement space. Novelty of the method lies also in the proposed way of synchronization of model signals enabling direct determination of the difference between time-of-flights (TOF) of annihilation quanta from the annihilation point to the detectors. The introduced method was validated using experimental data obtained by means of the double strip prototype of the J-PET detector and 22Na sodium isotope as a source of annihilation gamma quanta.The detector was built out from plastic scintillator strips with dimensions of 5 mm x 19 mm x 300 mm, optically connected at both sides to photomultipliers,from which signals were sampled by means of the Serial Data Analyzer.Using the introduced method, the spatial and TOF resolution of about 1.3 cm (?) and 125 ps (?) were established, respectively.
Test of a single module of the J-PET scanner based on plastic scintillators
P. Moskal, S. Niedzwiecki, T. Bednarski, E. Czerwinski, L. Kaplon, E. Kubicz, I. Moskal, M. Pawlik-Niedzwiecka, NG. Sharma, M. Silarski, M. Zielinski, N. Zon, P. Bialas, A. Gajos, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemien, M. Molenda, M. Palka, L. Raczynski, Z. Rudy, P. Salabura, A. Slomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki
abstract
A Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this paper we report on tests of a single detection module built out from the BC-420 plastic scintillator strip (with dimensions of 5 x 19 x 300 mm(3)) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the Ge-68 isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50 ps intervals. The time resolution of the prototype module was established to be better than 80 ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93 cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E approximate to 0.044/root E(MeV) and corresponds to the (sigma(E)/E of 7.5% at the Compton edge. (C) 2014 Elsevier B.V. All rights reserved.
Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR
B.P. Singh,..., W. Krzemień, S. Jowzaee, B. Kamys, P. Moskal, A. Wrońska, P. Salabura, J. Smyrski, Z. Rudy,
abstract
We address the possibility of accessing nucleon-to-pion (?N) Transition Distribution Amplitudes (TDAs) from p?p?e+e??0 reaction with the future ={P}ANDA detector at the FAIR facility. At high center of mass energy and high invariant mass of the lepton pair q2, the amplitude of the signal channel p?p?e+e??0 admits a QCD factorized description in terms of ?N TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring p?p?e+e??0 with the ={P}ANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, {it i.e.} p?p??+???0 were performed for the center of mass energy squared s=5 GeV2 and s=10 GeV2, in the kinematic regions 3.00.5 in the proton-antiproton center of mass frame. Results of the simulation show that the particle identification capabilities of the ={P}ANDA detector will allow to achieve a background rejection factor at the level of 108 (2?107) at low (high) q2 while keeping the signal reconstruction efficiency at around 40% and that a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 fb?1 of integrated luminosity. The future measurement of the signal channel cross section with ={P}ANDA will provide a new test of perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing ?N TDAs.
Determination of the eta '-Proton Scattering Length in Free Space
E. Czerwinski, P. Moskal, M. Silarski, SD. Bass, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, J. Smyrski, A. Taschner, M. Wolke, M. Zielinski
abstract
Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton beam of the cooler synchrotron COSY, we determine the excitation function for the pp --> pp eta' reaction close to threshold. Combining these data with previous results, we extract the scattering length for the eta'-proton potential in free space to be Re(alpha(p eta)') = 0 +/- 0.43 fm and Im(alpha(p eta)') = 0.37(-0.16)(+0.40) fm.
Test of a single module of the J-PET scanner based on plastic scintillators
P. Moskal, Sz. Niedźwiecki, T. Bednarski, E. Czerwiński, Ł. Kapłon, E. Kubicz, I. Moskal, M. Pawlik-Niedźwiecka, N.G. Sharma, M. Silarski, M. Zieliński, N. Zoń, P. Białas, A. Gajos, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, M. Pałka, L. Raczyński, Z. Rudy, P. Salabura, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki
abstract
Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E = 0.044/sqrt(E[MeV]) and corresponds to the sigma(E)/E of 7.5% at the Compton edge.
Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511 keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 ps (sigma).
Determination of the eta prime - proton scattering length in free space
E. Czerwiński, P. Moskal, M. Silarski, S. D. Bass, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, J. Smyrski, A. Täschner, M. Wolke, M. Zieliński
abstract
Taking advantage of both the high mass resolution of the COSY--11 detector and the high energy resolution of the low-emittance proton-beam of the Cooler Synchrotron COSY we determine the excitation function for the pp --> pp eta' reaction close-to-threshold. Combining these data with previous results we extract the scattering length for the eta'-proton potential in free space to be Re (a p eta') = 0 +/- 0.43 fm and Im a_(p eta') = 0.37^{+0.40}_{-0.16} fm.
Computing support for advanced medical data analysis and imaging
W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, S. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
We discuss computing issues for data analysis and image reconstruction of PET-TOF medical scanner or other medical scanning devices producing large volumes of data. Service architecture based on the grid and cloud concepts for distributed processing is proposed and critically discussed.
A novel method based solely on FPGA units enabling measurement of time and charge of analog signals in Positron Emission Tomography
M. Pałka, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article presents a novel technique for precise measurement of time and charge based solely on FPGA (Field Programmable Gate Array) device and few satellite discrete electronic components used in Positron Emission Tomography (PET). Described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of ? 10ps (rms) and thus enables sampling of signals in a voltage domain.
A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays
M. Silarski, E. Czerwiński, T. Bednarski, P. Moskal, P. Białas, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
All of the present methods for calibration and monitoring of TOF-PET scanner detectors utilize radioactive isotopes such as e.g. 22Na or 68Ge, which are placed or rotate inside the scanner. In this article we describe a novel method based on the cosmic rays application to the PET calibration and monitoring methods. The concept allows to overcome many of the drawbacks of the present methods and it is well suited for newly developed TOF-PET scanners with a large longitudinal field of view. The method enables also monitoring of the quality of the scintillator materials and in general allows for the continuous quality assurance of the PET detector performance.
3D PET image reconstruction based on the maximum likelihood estimation method (MLEM) algorithm
A. Słomski, Z. Rudy, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, P. Salabura, N. G. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
A positron emission tomography (PET) scan does not measure an image directly. Instead, a PET scan measures a sinogram at the boundary of the field-of-view that consists of measurements of the sums of all the counts along the lines connecting the two detectors. Because there is a multitude of detectors built in a typical PET structure, there are many possible detector pairs that pertain to the measurement. The problem is how to turn this measurement into an image (this is called imaging). Significant improvement in PET image quality was achieved with the introduction of iterative reconstruction techniques. This was realized approximately 20 years ago (with the advent of new powerful computing processors). However, three-dimensional imaging still remains a challenge. The purpose of the image reconstruction algorithm is to process this imperfect count data for a large number (many millions) of lines of response and millions of detected photons to produce an image showing the distribution of the labeled molecules in space.
Trigger-less and reconfigurable data acquisition system for positron emission tomography
G. Korcyl, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article is focused on data acquisition system (DAQ) designed especially to be used in positron emission tomography (PET) or single-photon emission computed tomography. The system allows for continuous registration of analog signals during measurement. It has been designed to optimize registration and processing of the information carried by signals from the detector system in PET scanner. The processing does not require any rejection of data with a trigger system. The proposed system possesses also an ability to implement various data analysis algorithms that can be performed in real time during data collection.
Determination of the map of efficiency of the Jagiellonian Positron Emission Tomograph (J-PET) detector with the GATE package
P. Kowalski, L. Raczyński, T. Bednarski, P. Białas, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
A novel PET detector consisting of strips of polymer scintillators is being developed by the J-PET Collaboration. The map of efficiency and the map of geometrical acceptance of the 2-strip J-PET scanner are presented. Map of efficiency was determined using the Monte Carlo simulation software GATE based on GEANT4. Both maps were compared using method based on the chi2 test.
Plastic scintillators for positron emission tomography obtained by the bulk polymerization method
Ł. Kapłon, A. Kochanowski, M. Molenda, P. Moskal, A. Wieczorek, T. Bednarski, P. Białas, E. Czerwiński, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillators, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.
J-PET analysis framework for the prototype TOF-PET detector
W. Krzemień, M. Silarski, K. Stola, D. Trybek, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
Novel TOF-PET scanner solutions demand, apart from the state of the art detectors, software for fast processing of the gathered data, monitoring of the whole scanner and reconstruction of the PET image. In this article we present an analysis framework for the novel STRIP-PET scanner developed by the J-PET collaboration in the Institute of Physics of the Jagiellonian University. This software is based on the ROOT package used in many particle physics experiments.
Database and data structure for the novel TOF-PET detector developed for J-PET project
E. Czerwiński, M. Zieliński, T. Bednarski, P. Białas, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W.Wiślicki, N. Zoń
abstract
The complexity of the hardware and the amount of data collected during the PET imaging process require application of modern methods of efficient data organization and processing. In this article we will discuss the data structures and the flow of collected data from the novel TOF-PET medical scanner which is being developed at the Jagiellonian University. The developed data format reflects: registration process of the gamma quanta emitted from positron-electron annihilation, Front-End Electronic (FEE) structure and required input information for the image reconstruction. In addition, the system database fulfills possible demands of the evolving J-PET project.
Calibration of photomultipliers gain used in the J-PET detector
T. Bednarski, E. Czerwiński, P. Moskal, P. Białas, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
Photomultipliers are commonly used in commercial PET scanner as devices which convert light produced in scintillator by gamma quanta from positron-electron annihilation into electrical signal. For proper analysis of obtained electrical signal, a photomultiplier gain curve must be known, since gain can be significantly different even between photomultipliers of the same model. In this article we describe single photoelectron method used for photomultipliers calibration applied for J-PET scanner, a novel PET detector being developed at the Jagiellonian University. Description of calibration method, an example of calibration curve and gain of few R4998 Hamamatsu photomultipliers are presented.
List-mode reconstruction in 2D strip PET
P. Białas, J. Kowal, A. Strzelecki, T. Bednarski, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, P. Moskal, S. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
Using a theory of list-mode maximum likelihood
expectation-maximization (MLEM) algorithm, in this contribution,
we present a derivation of the system response
kernel for a novel positron emission tomography (PET)
detector based on plastic scintillators.
Tracking with Straw Tubes in the PANDA Experiment
M. Bragadireanu, D. Pietreanu, ME. Vasile, M. Idzik, D. Przyborowski, P. Kulessa, K. Pysz, J. Biernat, S. Jowzaee, G. Korcyl, M. Palka, P. Salabura, J. Smyrski, D. Bettoni, E. Fioravanti, I. Garzia, M. Savrie, P. Gianotti, V. Lucherini, E. Pace, M. Mertens, H. Ohm, S. Orfanitski, J. Ritman, V. Serdyuk, P. Wintz, S. Dobbs, A. Tomaradze, GL. Boca, S. Costanza, P. Genova, L. Lavezzi, P. Montagna, A. Rotondi, S. Spataro
abstract
The PANDA spectrometer will be built at the FAIR facility at Darmstadt (Germany) to perform accurate tests of the strong interaction through (p) over barp and (p) over barA annihilation studies. The charged particle tracking at PANDA will be done using both solid state and gaseous detectors. Among the latter, two straw tube detector systems will be built [ 1]. The cylindrical, central straw tube tracker features a high spatial and momentum resolution for a wide range of particle momenta from about 8 GeV/c down to a few 100 MeV/c, together with particle identification in the momentum region below about 1 GeV/c by measuring the specific energy-loss. A new technique, based on self-supporting straw double layers with intrinsic wire tension developed for the COSY-TOF straw tracker [ 2], has been adopted for the PANDA trackers. The development of the readout electronics for the straw tubes is ongoing. Prototypes have been produced and used to instrument straw tube modules that have been tested with cosmic rays and proton beams. Design issues of the PANDA straw tubes, together with the results of the prototype tests are presented.
Search for the eta-mesic He-4 with WASA-at-COSY
W. Krzemien, P. Moskal, J. Smyrski, M. Skurzok
abstract
We conduct a search for the He-eta bound state with the WASA-at-COSY facility measuring the excitation functions for the reaction channels: dd -> (3)Hep pi(-) and dd -> (3)Hen pi(0), where the outgoing N-pi pairs originate from the conversion of the eta meson on a nucleon inside the He nucleus. Two dedicated experiments were performed at the Cooler Synchrotron COSY-Julich with the WASA detector. The analysis of the 2008 data shows no signal of the He-4 - eta bound state. An upper limit for the cross-section for the bound state formation and decay in the process dd -> (He-4 - eta)(bound) -> (3)Hep pi(-), was determined at the 90 % confidence level. In November 2010 a new data set was collected.
Simulations of gamma quanta scattering in a single module of the J-PET detector
K. Szymański, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, P. Witkowski, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article describes simulations of scattering of annihilation gamma quanta in a strip of plastic scintillator. Such strips constitute basic detection modules in a newly proposed Positron Emission Tomography which utilizes plastic scintillators instead of inorganic crystals. An algorithm simulating chain of Compton scatterings was elaborated and series of simulations have been conducted for the scintillator strip with the cross section of 5 mm x 19 mm. Obtained results indicate that secondary interactions occur only in the case of about 8% of events and out of them only 25% take place in the distance larger than 0.5 cm from the primary interaction. It was also established that light signals produced at primary and secondary interactions overlap with the delay which distribution is characterized by FWHM of about 40 ps.
Application of WLS strips for position determination in Strip PET tomograph based on plastic scintillators
J. Smyrski, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
A method of determination of a gamma quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. Application of this method for improvement of position resolution in newly proposed PET detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in reconstruction of images which occurs in the presently used Positron Emission Tomography scanners.
Particle identification using the time-over-threshold measurements in straw tube detectors
S. Jowzaee, E. Fioravanti, P. Gianotti, M. Idzik, G. Korcyl, M. Palka, D. Przyborowski, K. Pysz, J. Ritman, P. Salabura, M. Savrie, J. Smyrski, P. Strzempek, P. Wintz
abstract
The identification of charged particles based on energy losses in straw tube detectors has been simulated. The response of a new front-end chip developed for the PANDA straw tube tracker was implemented in the simulations and corrections for track distance to sense wire were included. Separation power for p-K, p-pi and K-pi pairs obtained using the time-over-threshold technique was compared with the one based on the measurement of collected charge. (C) 2012 Elsevier B.V. All rights reserved.
TOF-PET detector concept based on organic scintillators
P. Moskal, T. Bednarski, P. Białas, M. Ciszewska, E. Czerwiński, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka-Cupiał, G. Korcyl, W. Krzemień, K. Łojek, J. Majewski, W. Migdał, M. Molenda, S. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, M. Silarski, A. Słomski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
In this contribution we present a new concept of the large acceptance detector systems based on organic scintillators which may allow for simultaneous diagnostic of large fraction of the human body. Novelty of the concept lies in employing large blocks of polymer scintillators instead of crystals as detectors of annihilation quanta, and in using predominantly the timing of signals instead of their amplitudes.
Strip-PET: a novel detector concept for the TOF-PET scanner
P. Moskal, T. Bednarski, P. Białas, M. Ciszewska, E. Czerwiński, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka-Cupiał, G. Korcyl, W. Krzemień, K. Łojek, J. Majewski, W. Migdał, M. Molenda, S. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, M. Silarski, A. Słomski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
We briefly present a design of a new PET scanner based on
strips of polymer scintillators arranged in a barrel constituting
a large acceptance detector. The solution proposed is based on
the superior timing properties of the polymer scintillators. The
position and time of the reaction of the gamma quanta in the
detector material will be determined based on the time of arrival
of light signals to the edges of the scintillator strips.
The Straw Tube Trackers of the (P)over-barANDA Experiment
P. Gianotti, V. Lucherini, E. Pace, GL. Boca, S. Costanza, P. Genova, L. Lavezzi, P. Montanga, A. Rotondi, M. Bragadireanu, ME. Vasile, D. Pietreanu, J. Biernat, S. Jowzaee, G. Korcyl, M. Palka, P. Salabura, J. Smyrski, T. Fiutowski, M. Idzik, D. Przyborowski, K. Korcyl, P. Kulessa, K. Pysz, S. Dobbs, A. Tomaradze, D. Bettoni, E. Fioravanti, I. Garzia, M. Savrie, V. Kozlov, M. Mertens, H. Ohm, S. Orfanitski, J. Ritman, V. Serdyuk, P. Wintz, S. Spataro
abstract
The (P) over bar ANDA experiment will be built at the FAIR facility at Darmstadt (Germany) to perform accurate tests of the strong interaction through (p) over barp and (p) over barA annihilation's studies. To track charged particles, two systems consisting of a set of planar, closed-packed, self-supporting straw tube layers are under construction. The (P) over bar ANDA straw tubes will have also unique characteristics in term of material budget and performance. They consist of very thin mylar-aluminized cathodes which are made self-supporting by means of the operation gas-mixture over-pressure. This solution allows to reduce at maximum the weight of the mechanical support frame and hence the detector material budget. The (P) over bar ANDA straw tube central tracker will not only reconstruct charged particle trajectories, but also will help in low momentum (< 1 GeV) particle identification via dE/dx measurements. This is a quite new approach that <(P)over bar>ANDA tracking group has first tested with detailed Monte Carlo simulations, and then with experimental tests of detector prototypes. This paper addresses the design issues of the (P) over bar ANDA straw tube trackers and the performance obtained in prototype tests.
Technical Design Report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
W. Erni, ..., S. Jowzaee, M. Kajetanowicz, B. Kamys, S. Kistryn, G. Korcyl, K. Korcyl, W. Krzemień, A. Magiera, P. Moskal, M. Palka, Z. Rudy, P. Salabura, J. Smyrski, A. Wrońska et al.
abstract
This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM-stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy-loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole Panda scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
Overview of the PANDA experiment
J. Smyrski
abstract
The PANDA detector at FAIR, Darmstadt, is designed for measurements of reactions induced by high intensity antiproton beams with a momentum between 1.5 GeV/c and 15 GeV/c interacting with hydrogen as well as nuclear targets. Basic subsystems of PANDA including magnets and target, tracking detectors, particle identification system, calorimeters and data acquisition are described. (C) 2012 Published by Elsevier B.V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.
Tracking with Straw Tubes in the PANDA Experiment
P. Gianotti, V. Lucherini, E. Pace, K. Kozlov, H. Ohm, S. Orfanitski, M. Mertens, J. Ritman, M. Roeder, V. Serdyuk, P. Wintz, M. Idzik, D. Przyborowski, S. Jowzaee, M. Kajetanowicz, G. Korcyl, P. Salabura, J. Smyrski, P. Kulessa, K. Pysz, G. Boca, S. Costanza, L. Lavezzi, P. Montagna, A. Rotondi, M. Savrie, O. Levitskaya, A. Kashchuk
abstract
Tracking charged particles is one of the essential tasks of the PANDA experiment, providing information about primary and secondary decay vertices, momenta and type of charged particles emitted after antiproton-proton annihilation, Different tracking devices are under construction for the PANDA spectrometer and among them the two straw tube trackers, A new technique, based on the use of straw tubes operated at over-pressure has been adopted allowing the construction of self-supporting modules avoiding heavy mechanical frames.
Search for eta-mesic Helium with the WASA-at-COSY detector
W. Krzemien, P. Moskal, J. Smyrski, M. Skurzok
abstract
A search for the He-4 - eta bound state via exclusive measurement of the excitation function for the dd -> He-3 p pi(-) reaction, was performed at the Cooler Synchrotron COSY-Julich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta production in the dd -> He-4 eta reaction at 2.336 GeV/c. The corresponding excess energy in the He-4 - eta system varied from -51.4 MeV to 22 MeV. The shape of the excitation function for the dd -> (3)Hep pi(-) was examined. No signal of the He-4 - eta bound state was observed in the excitation function.
Novel detector systems for the Positron Emission Tomography
P. Moskal, P. Salabura, M. Silarski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
In this contribution we describe a novel solution for the construction of Positron Emission Tomograph. We present
the device allowing for determination of the impact position as well as time and depth of interaction of the annihilation gamma
quanta. The device is comprised of scintillation chamber consisting of organic scintillators surrounding the body of the patient.
We discuss two possible solutions: (i) the tomograph built out of scintillator strips, and (ii) the tomograph built out of the scintillator
plates. The application of the fast scintillators will enable to take advantage of the difference between time of the registration of
the annihilation quanta. The invented method will permit to use a thick layers of detector material with the possibility of measuring
the depth of the gamma quantum interaction (DOI) and the determination of their time of fl ight (TOF), and will allow for increasing
the size of the diagnostic chamber without a signifi cant increase of costs. The method is a subject of two patent applications
[1, 2] which are based on the techniques used in the particle physics experiments [3, 4].
SEARCH FOR THE eta-MESIC NUCLEI BY MEANS OF COSY-11, WASA-AT-COSY AND COSY-TOF DETECTOR SYSTEMS
P. Moskal, J. Smyrski
abstract
We review status and perspectives of the search for the light eta-mesic nuclei using COSY-11, WASA-at-COSY and COSY-TOF detector systems.
Search for the eta-mesic nuclei by means of COSY-11, WASA-at-COSY and COSY-TOF detector systems
P. Moskal, J. Smyrski
abstract
We review status and perspectives of the search for the light eta-mesic nuclei using COSY-11, WASA-at-COSY and COSY-TOF detector systems.
Determination of the total width of the eta-prime meson
E. Czerwiński, P. Moskal, D. Grzonka, R. Czyżykiewicz, D. Gil, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, J. Zdebik, M. Zieliński, W. Zipper
abstract
Taking advantage of both the low-emittance proton beam of the cooler synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the eta-prime meson was measured with a resolution of 0.33??MeV/c2 (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp->pp eta-prime events, the total width of the eta-prime meson was determined to be Gamma(eta-prime) = 0.226+-0.017(stat)+-0.014(syst)??MeV/c2.
Two-proton correlation function for the pp -> pp + eta and pp to pp + pions reactions
P. Klaja, P. Moskal, E. Czerwiński, R. Czyżykiewicz, A. Deloff, D. Gil, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, J. Zdebik, M. Zieliński, W. Zipper
abstract
For the very first time, the correlation femtoscopy method is applied to a kinematically complete measurement of meson production in the collisions of hadrons. A two-proton correlation function was derived from the data for the pp -> ppX reaction, measured near the threshold of eta meson production. A technique developed for the purpose of this analysis permitted the correlation function to be established separately for the production of the pp + eta and of the pp + pions systems. The shape of the two-proton correlation function for pp-eta differs from that for pp(pions) and both do not show a peak structure, opposite to the results determined for inclusive measurements of heavy ion collisions.
Two-proton correlation function for the pp -> pp plus eta and pp -> pp plus pions reactions
P. Klaja, P. Moskal, E. Czerwinski, R. Czyzykiewicz, A. Deloff, D. Gil, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, J. Zdebik, M. Zielinski, W. Zipper
abstract
For the very first time, the correlation femtoscopy method is applied to a kinematically complete measurement of meson production in the collisions of hadrons. A two-proton correlation function was derived from the data for the pp -> ppX reaction, measured near the threshold of eta meson production. A technique developed for the purpose of this analysis permitted the correlation function to be established separately for the production of the pp + eta and of the pp + pions systems. The shape of the two-proton correlation function for pp eta differs from that for pp(pions) and both do not show a peak structure, opposite to the results determined for inclusive measurements of heavy ion collisions.
Upper limit of the total cross section for the pn->pn eta-prime reaction
J. Klaja, P. Moskal, S. D. Bass, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemień, W. Oelert, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, J. Zdebik, M. Zieliński, W. Zipper
abstract
The upper limit of the total cross section for the pn->pneta-prime reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R(eta-prime)=sigma(pn->pneta-prime)/sigma(pp->ppeta-prime) with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta-prime meson and suggests nonidentical production mechanisms for eta and eta-prime mesons.
Measurement of the invariant mass distributions fot he pp->pp eta-prime reaction at excess energy of Q = 16.4 MeV
P. Klaja, P. Moskal, E. Czerwiński, R. Czyżykiewicz, A. Deloff, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, K. Nakayama, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, J. Zdebik, M. Zieliński, W. Zipper
abstract
The proton?proton and proton? invariant mass distributions have been determined for the reaction at an excess energy of . The measurement was carried out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the reaction and reveal an enhancement for large relative proton?proton momenta. This result, together with the fact that the proton?? interaction is much stronger that the proton? interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson.
Upper limit of the total cross section for the pn -> pn eta' reaction
J. Klaja, P. Moskal, SD. Bass, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemien, W. Oelert, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zielinski, W. Zipper
abstract
The upper limit of the total cross section for the pn -> pn eta' reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R-eta' = sigma(pn -> pn eta')/sigma(pp -> pp eta') with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta' meson and suggests nonidentical production mechanisms for eta and eta' mesons.
Measurement of the invariant mass distributions for the pp -> pp eta ' reaction at excess energy of Q=16.4 MeV
P. Klaja, P. Moskal, E. Czerwinski, R. Czyzykiewicz, A. Deloff, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, K. Nakayama, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, J. Zdebik, M. Zielinski, W. Zipper
abstract
The proton-proton and proton-eta' invariant mass distributions have been determined for the pp -> pp eta' reaction at an excess energy of Q = 16.4 MeV. The measurement was carried Out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the pp -> pp eta reaction and reveal an enhancement for large relative proton-proton momenta. This result, together with the fact that the proton-eta interaction is Much stronger that the proton-eta' interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson. (C) 2010 Elsevier B.V. All rights reserved.
Invariant-mass distributions for the pp -> pp eta reaction at Q=10 MeV
P. Moskal, R. Czyzykiewicz, E. Czerwinski, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, MJ. Zielinski, W. Zipper
abstract
Proton-proton and proton-eta invariant-mass distributions and the total cross-section for the pp -> pp eta reaction have been determined near the threshold at an excess energy of Q = 10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q = 15.5 MeV and Q = 40 MeV.
Invariant mass distributions for the pp->pp eta reaction at Q = 10 MeV
P. Moskal, R. Czyżykiewicz, E. Czerwiński, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zieliński, W. Zipper
abstract
Proton-proton and proton-eta invariant-mass distributions and the total cross-section for the pp -> pp h reaction have been determined near the threshold at an excess energy of Q = 10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q = 15.5 MeV and Q = 40 MeV.
Generalized Dalitz plot analysis of the near-threshold pp -> ppK(+)K(-) reaction in view of the K+K- final state interaction
M. Silarski, P. Moskal, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, M. Zielinski, W. Zipper, J. Zdebik
abstract
The excitation function for the pp -> ppK(+)K(-) reaction revealed a significant enhancement close to threshold that may plausibly be assigned to the influence of the pK(-) and K+K- final-state interactions. In an improved reanalysis of COSY-11 data for the pp -> ppK(+)K(-) reaction at excess energies of Q = 10 and 28 MeV, including the proton-K- interaction, the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow us to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK(+)K(-) system as derived from the COSY-ANKE data. Finally, based for the first time on the low-energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be vertical bar Re(a(K+K-))vertical bar = 0.5(-0.5)(+4.0) fm and Im(a(K+K-)) = 3.0 +/- 3.0 fm.
Generalized Dalitz plot analysis of the near-threshold pp->ppK+K- reaction in view of the K+K- final state interaction
M. Silarski, P. Moskal, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Täschner, P. Winter, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper, J. Zdebik
abstract
The excitation function for the pp->ppK+K- reaction revealed a significant enhancement close to threshold which may plausibly be assigned to the influence of the pK- and K+K- final state interactions. In an improved reanalysis of COSY-11 data for the pp-> ppK+K- reaction at excess energies of Q = 10 MeV and 28 MeV including the proton-K- interaction the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK+K- system as derived from the COSY-ANKE data. Finally, based for the first time on the low energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be |Re(a_K+K-)| = 0.5 + 4.0 -0.5 fm and Im(a_K+K-) = 3.0 +- 3.0 fm.
Near-threshold production of the eta meson via the quasi-free pn->pneta reaction
P. Moskal, R. Czyżykiewicz, H.-H. Adam, S. D. Bass, A. Budzanowski, E. Czerwiński, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taeschner, M. Wolke, P. Wuestner, M. Zieliński, W. Zipper, J. Zdebik
abstract
Total cross sections for the quasifree pn->pn? reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp?pp? reaction by a factor of about 3 in contrast to the factor of 6 established for higher excess energies. To large extent, the observed decrease of the ratio sigma(pn->pn?)/sigma(pp->pp?) toward threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final-state interactions. The experiment was conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton-neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn?pn? reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.
Isospin dependence of the eta-prime meson production in nucleon-nucleon collisions
J. Przerwa, P. Moskal, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemień, W. Oelert, C. Piskor-Ignatowicz, J. Ritman, B. Rejdych, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zieliński, W. Zipper
abstract
A comparison of the close-to-threshold total cross section for the eta prime production in pp -> pp eta prime and pn -> pn eta prime reactions constitutes a tool to investigate the eta prime meson structure and the reaction mechanism in the channels of isospin I=0 and I=1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content of the eta prime meson. In this contribution we present preliminary results of measurement of the quasi-free production of the eta prime meson in the proton-neutron collisions conducted using the COSY-11 facility.
ISOSPIN DEPENDENCE OF THE eta ' MESON PRODUCTION IN NUCLEON-NUCLEON COLLISIONS
J. Przerwa, P. Moskal, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemien, W. Oelert, C. Piskor-Ignatowicz, J. Ritman, B. Rejdych, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, MJ. Zielinski, W. Zipper
abstract
A comparison of the close-to-threshold total cross section for the eta' production in pp -> pp eta' and pn -> pn eta' reactions constitutes a tool to investigate the eta' meson structure and the reaction mechanism in the channels of isospin I = 0 and I = 1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content of the eta' meson. In this contribution we present preliminary results of measurement of the quasifree production of the eta' meson in the proton-neutron collisions conducted using the COSY-11 facility.
SEARCH FOR THE He-3-eta BOUND STATE AT COSY-11
W. Krzemien, J. Smyrski, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, W. Oelert, J. Przerwa, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, MJ. Zielinski, W. Zipper
abstract
We have measured excitation function for dp -> ppp pi(-) reaction near the. production threshold. We observe an enhancement of the counting rate above the threshold which can originate from the production of the. meson in the reaction dp -> He-3 eta and its subsequent absorption on neutron in the 3He nucleus leading to creation of the p pi(-) pair.
Search for the 3He-eta bound state at COSY-11
W. Krzemien, J. Smyrski, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, W. Oelert, J. Przerwa, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, A. Taeschner, M. Wolke, P. Wuestner, J. Zdebik, M. Zieliński, W. Zipper
abstract
We have measured excitation function for dp -> ppp_pi- reaction near the eta production threshold. We observe an enhancement of the counting rate above the threshold which can originate from the production of the eta meson in the reaction dp -> 3He eta and its subsequent absorption on neutron in the 3He nucleus leading to creation of the p_pi- pair.
Near-threshold production of the eta meson via the quasifree pn -> pn eta reaction
P. Moskal, R. Czyzykiewicz, HH. Adam, SD. Bass, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, M. Zielinski, W. Zipper, J. Zdebik
abstract
Total cross sections for the quasifree pn -> pn eta reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pn -> pn eta reaction by a factor of about 3 in contrast to the factor of 6 established for higher excess energies. To large extent, the observed decrease of the ratio s(pn -> pn eta)/s=sigma(pn -> pn eta) toward threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final-state interactions. The experiment was conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton- neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn -> pn eta reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.
A threshold Cherenkov detector for K+/pi(+) separation using silica aerogel
R. Siudak, A. Budzanowski, A. Chatterjee, H. Clement, E. Dorochkevitsch, J. Ernst, P. Hawranek, F. Hinterberger, R. Jahn, L. Jarczyk, R. Joosten, K. Kilian, D. Kirillov, S. Kliczewski, D. Kolev, M. Kravcikova, H. Machner, A. Magiera, G. Martinska, F. Massmann, J. Munkel, N. Piskunov, D. Protic, J. Ritman, P. von Rossen, B. Roy, I. Sitnik, I. Slepnev, J. Smyrski, R. Tsenov, K. Ulbrich, J. Urban, G. Vankova, GJ. Wagnerj, R. Ziegler
abstract
A new threshold Cherenkov detector has been built for the detection of charged pions in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n = 1.05 is applied as a radiator. The detector exhibits a very high detection efficiency for pions with momenta >= 900MeV/c. Using two Cherenkov detectors in series a very high pion suppression factor of 10(5) was achieved. (C) 2008 Elsevier B.V. All rights reserved.
Study of the hadronic production of kaon pairs below the threshold for the phi meson
P. Moskal, M. Silarski, A. Budzanowski, E. Czerwinski, R. Czyzykiewic, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, MJ. Zielinski, W. Zipper, J. Zdebik
abstract
The near threshold production of K(+)K(-) pairs in proton-proton collisions has been investigated at the cooler synchrotron COSY below and above the threshold for the phi meson using the COSY-11 and ANKE facilities., respectively. The excitation function determined for the pp -> ppK(+)K(-) reaction revealed a statistically significant enhancement close to the threshold which may plausibly be assigned to the influence of the K(-)p interaction. In addition, observed consistently by both groups, a strong enhancement at low values of the ratio of the K(-)p to K(+)p invariant mass distributions shows that the proton interacts much stronger with K(-) than with K(+). In this report we focus on the measurements performed by the COSY-11 collaboration. We explain the experimental method used and present main results of completed analyses as well as a new qualitative elaboration of the ppK(+)K(-) events population on the Goldhaber plot. We conclude with the observation that event densities increase at the region where the influence from the K(+)K(-) interaction is expected.
Near threshold production of the pseudoscalar mesons at the COSY-11 facility
P. Moskal, R. Czyzykiewicz, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, X. Kilian, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Winter, P. Wustner, M. Zielinski, W. Zipper
abstract
We summarise measurements of the COSY-11 collaboration concerning the excitation functions of the near threshold pseudoscalar meson production in the proton-proton interaction. The results are discussed in the context of the meson-nucleon and hyperon-nucleon interactions. We conclude that the eta-proton interaction is significantly stronger than the eta'-proton interaction. Similarly, we found that the hyperon Lambda interacts with the nucleon considerably stronger than the hyperon Sigma, and that the interaction of K--proton is much stronger than this of the K+-proton.
PROTOTYPE DRIFT CHAMBER FOR TRACKING AT SMALL ANGLES IN THE PANDA EXPERIMENT
J. Smyrski, P. Hawranek, W. Krzemien, P. Salabura, A. Wronska
abstract
A prototype drift chamber for tracking at small angles in the high rate environment of the PANDA experiment has been built. The chamber contains 1 cm x 1 cm drift cells arranged in two double layers. The most central wires are mounted on insulating rings surrounding the beam pipe. Results of the chamber tests with a beam of up to 5.10(6) protons per second indicate a drop of detection efficiency by about 5% at the highest measured flux of 0.2 MHz/cm(2).
Dynamics of the near threshold eta meson production in proton-proton interaction
R. Czyzykiewicz, P. MoSkal, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Hodana, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, K. Ulbrich, P. Winter, M. Wolke, P. Wustner, M. Zielinski, W. Zipper
abstract
We present the results of measurements of the analysing power for the pp -> pp eta reaction at the excess energies of Q = 10 and 36 MeV, and interpret these results within the framework of the meson exchange models. The determined values of the analysing power at both excess energies are consistent with zero implying that the eta meson is produced predominantly in s-wave.
Study of the He-3-eta system in d-p collisions
J. Smyrski, HH. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, A. Siemaszko, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
We have measured excitation functions for the dp -> He-3 X, (X = pi(0),eta) channels near the eta production threshold. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target. The excitation function for the reaction dp -> He-3 pi(0) does not show any structure which could originate from the decay of He-3 - eta bound state. We measured also the threshold excitation curve for the dp -> He-3 X process, however, contrary to the SATURNE results, we observe no cusp near the eta threshold.
Measurement of the dp -> He-3 eta reaction near threshold
J. Smyrski, HH. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, T. Mersmann, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Total and differential cross sections for the dp -> He-3 eta reaction have been measured near threshold for He-3 center-of-mass momenta in the range from 17.1 MeV/c to 87.5 MeV/c. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target detecting the He-3 ejectiles with the COSY-11 facility. The forward-backward asymmetries of the differential cross sections deviate clearly from zero for center-of-mass momenta above 50 MeV/c indicating the presence of higher partial waves in the final state. Below 50 MeV/c center-of-mass momenta a fit of the final state enhancement factor to the data of the total cross sections results in the He-3-eta scattering length of vertical bar a vertical bar = 4.3 +/- 0.5fm. (C) 2007 Elsevier B.V. All rights reserved.
Mechanism of near-threshold production of the eta meson
R. Czyzykiewicz, P. Moskal, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Hodana, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, K. Ulbrich, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Measurements of the analyzing power for the pp -> pp eta reaction have been performed at excess energies of Q=10 and 36 MeV. The determined analyzing power is essentially consistent with zero, implying dominance of the s wave at both excess energies. The angular dependence of the analyzing power, combined with the isospin dependence of the total cross section for the eta meson production in nucleon-nucleon collisions, reveal that the excitation of the nucleon to the S-11(1535) resonance is predominantly due to the exchange of the pi meson between the colliding nucleons.
Eta and eta-prime mesons production at COSY-11
P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, B. Rejdych, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
The low emittance and small momentum spread of the proton and deuteron beams of the Cooler Synchrotron COSY combined with the high mass resolution of the COSY-11 detection system permit to study the creation of mesons in the nucleon-nucleon interaction down to the fraction of MeV with respect to the kinematical threshold. At such small excess energies, the ejectiles possess low relative momenta and are predominantly produced with the relative angular momentum equal to zero. Taking advantage of these conditions we have performed investigations aiming to determine the mechanism of the production of eta and eta' mesons in the collision of hadrons as well as the hadronic interaction of these mesons with nucleons and nuclei. In this proceedings we address the ongoing studies of the spin and isospin dependence for the production of the eta and eta' mesons in free and quasi-free nucleon-nucleon collisions. New results on the spin observables for the vec(p)p --> pp eta reaction, combined with the previously determined total cross section isospin dependence, reveal a statistically significant indication that the excitation of the nucleon to the S11(1535) resonance, the process which intermediates the production of the eta meson in the nucleon-nucleon interactions, is predominantly due to the exchange of the pi meson between the colliding nucleons.
General thoughts to the Kaon pair production in the threshold region
W. Oelert, H.-H. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Simple--minded thoughts about the cross sections for the reactions pp-->ppK+K- and pp-->ppK0K0 are presented, which certainly do not account for the complex coupled channel problem but rather provide some ideas into the mutual reaction dynamics.
Study of the production mechanism of the eta meson by means of analysing power measurements
R. Czyżykiewicz, P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwiński, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, B. Lorentz, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, H. Rohdjess, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, K. Ulbrich, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
Information about the production mechanism of the eta meson in proton-proton collisions can be inferred by confronting the experimental studies on the analysing power for the p(pol)p --> pp eta reaction with the theoretical predictions of this observable. Results show that the predictions of pure pseudoscalar- or vector meson exchange model are insufficient to describe the analysing powers.
Near threshold eta meson production in dp collisions
C. Piskor-Ignatowicz, J. Smyrski, P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, J. Majewski, W. Oelert, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
Preliminary results of recent measurements of the near threshold eta meson production in the dp-->dp eta reaction are presented. The experiment was performed at the COSY-Juelich accelerator with the use of the COSY-11 detection system. Data were taken for three values of deuteron beam momenta corresponding to excess energies of 3.2, 6.1 and 9.2 MeV. The energy dependence of the total cross section confirms a strong effect of the final state interaction.
General thoughts to the kaon pair production in the threshold region
W. Oelert, HH. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Simple-minded thoughts about the cross sections for the reactions pp -> ppK(+)K(-) and pp. ppK(0)K(0) are presented, which certainly do not account for the complex coupled channel problem but rather provide some ideas into the mutual reaction dynamics.
Study of the production mechanism of the eta meson by means of analysing power measurements
R. Czyzykiewicz, P. Moskal, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, B. Lorentz, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, H. Rohdjess, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, K. Ulbrich, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Information about the production mechanism of the eta meson in proton-proton collisions can be inferred by confronting the experimental studies on the analysing power for the (p) over right arrowp -> pp eta reaction with the theoretical predictions of this observable. The determined analysing powers for Q=10 MeV and Q=36 MeV are consistent with zero. Results show that the predictions of pure pseudoscalar meson exchange model fairly describe the experimental data, while the predictions of pure vector meson exchange dominance model disagree with the data at the level of 4.3 sigma.
Near threshold eta meson production in dp collisions
C. Piskor-Ignatowicz, J. Smyrski, P. Moskal, HH. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, J. Majewski, W. Oelert, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Preliminary results of recent measurements of the near threshold. meson production in the dp -> dp eta reaction are presented. The experiment was performed at the COSY-Juelich accelerator with the use of the COSY-11 detection system. Data were taken for three values of deuteron beam momenta corresponding to excess energies of 3.2, 6.1 and 9.2 MeV. The energy dependence of the total cross section con. rms a strong e. ect of the. nal state interaction.
Study of the low energy interaction of hadrons at COSY-11
P. Moskal, R. Czyżykiewicz, E. Czerwiński, D. Grzonka, A. Budzanowski, D. Gil, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
abstract
We summarize the studies of the low energy hadronic interaction of the KK and pK system performed by the COSY-11 collaboration. We discuss also the question of the existence of the ??3He bound state in the context of the experiments conducted by means of the COSY-11 facility
Measurement of the dp -> He-3 eta reaction near threshold
J. Smyrski, H.-H. Adam, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, T. Mersmann, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
Total and differential cross sections for the dp --> 3He eta reaction have been measured near threshold for 3He center-of-mass momenta in the range from 17.1 MeV/c to 87.5 MeV/c. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target detecting the 3He ejectiles with the COSY-11 facility. The forward-backward asymmetries of the differential cross sections deviate clearly from zero for center-of-mass momenta above 50 MeV/c indicating the presence of higher partial waves in the final state. Below 50 MeV/c center-of-mass momenta a fit of the final state enhancement factor to the data of the total cross sections results in the 3He eta scattering length of a = |2.9 +/- 0.6| + i (3.2 +/- 0.4) fm.
Direct measurement of the total width of the eta prime meson
E. Czerwiński, P. Moskal, D. Grzonka, A. Budzanowski, R. Czyżykiewiczy, D. Gil, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
abstract
Using stochastically cooled proton beam of the cooler synchrotron COSY and the COSY-11 apparatus we have measured the mass distribution of the eta prime meson producing it via the pp->ppeta' reaction. The preliminary analysis shows that the achieved experimental mass resolution amounts to about 0.3 MeV (FWHM). Such precision with about 2300 events gathered at five excess energies should permit for the extraction of the width of the eta' meson with an accuracy of about 10 keV. In this article we describe the method of the mea-surement and present preliminary results.
Hadronic He-3 eta production near threshold
H.-H. Adam, I. Geck, A. Khoukaz, T. Lister, R. Santo, S. Steltenkamp, A. Täschner, E. Czerwiński, R. Czyżykiewicz, M. Janusz, L. Jarczyk, B. Kamys, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, J. Smyrski, D. Grzonka, K. Kilian, W. Oelert, T. Sefzick, P. Winter, M. Wolke, P. Wüstner, A. Budzanowski, T. Rożek, M. Siemaszko, W. Zipper
abstract
Measurements of ? meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Jülich). Results on total and differential cross sections for the pd?3He? reaction are presented at five excess energies between Q=5.0 and Q=40.6 MeV. The angular distributions show a transition from an almost isotropic emission close to threshold to a highly anisotropic distribution at higher excess energies. The total cross sections reveal a strong ?-3He final state interaction, corresponding to a scattering length of |?(a)|=(4.2?0.5) fm and ?(a)=(0.4?1.9) fm
Study of the He-3 eta system in d p collisions
J. Smyrski, H.-H. Adam, A.Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
We have measured excitation functions for the d+p->3He+X, (X=pi0, eta) channels near the eta production threshold. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target. The excitation function for the reaction d+p->3He+pi0 does not show any structure which could originate from the decay of 3He-eta bound state. We measured also the threshold excitation curve for the d+p->3He+X process, however, contrary to the SATURNE results, we observe no cusp near the eta threshold.
Mechanism of the close-to-threshold production of the eta meson
R. Czyzykiewicz, P. Moskal, H. -H. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Hodana, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, K. Ulbrich, P. Winter, M. Wolke, P. Wuestner, W. Zipper
abstract
Measurements of the analysing power for the p(pol)p --> ppeta reaction have been performed in the close-to-threshold energy region at beam momenta of p_{beam}=2.010 and 2.085 GeV/c, corresponding to excess energies of Q=10 and 36 MeV, respectively. The determined analysing power is essentially consistent with zero implying that the eta meson is produced predominantly in the s-wave at both excess energies. The angular dependence of the analysing power, combined with the hitherto determined isospin dependence of the total cross section for the eta meson production in nucleon-nucleon collisions, reveal a statistically significant indication that the excitation of the nucleon to the S_{11}(1535) resonance, the process which intermediates the production of the eta meson, is predominantly due to the exchange of the pi meson between the colliding nucleons.
Hadronic He-3 eta production near threshold
HH. Adam, I. Geck, A. Khoukaz, T. Lister, R. Santo, S. Steltenkamp, A. Taschner, E. Czerwimski, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, J. Smyrski, D. Grzonka, K. Kilian, W. Oelert, T. Sefzick, P. Winter, M. Wolke, P. Wustner
abstract
Measurements of eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Julich). Results on total and differential cross sections for the pd -> He-3 eta reaction are presented at five excess energies between Q=5.0 and Q=40.6 MeV. The angular distributions show a transition from an almost isotropic emission close to threshold to a highly anisotropic distribution at higher excess energies. The total cross sections reveal a strong eta-He-3 final state interaction, corresponding to a scattering length of vertical bar(a)vertical bar=(4.2 +/- 0.5) fm and (a)=(0.4 +/- 1.9) fm.
Experimental study of the pd -> He-3 K+K- and pd -> He-3 phi reactions close to threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, R. Joosten, K. Kilian, A. Kozela, H. Machner, A. Magiera, J. Munkel, P. von Neumann-Cosel, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, R. Tolle, C. Wilkin
abstract
Two-kaon production in proton-deuteron collisions has been studied at three energies close to threshold using a calibrated magnetic spectrograph to measure the final He-3 and a vertex detector to measure the K+K- pair. Differential and total cross sections are presented for the production of phi-mesons, decaying through phi -> K+K-, as well as for prompt K+K- production. The prompt production seems to follow phase space in both its differential distributions and in its energy dependence. The amplitude for the pd -> He-3 phi reaction varies little for excess energies below 22 MeV and the value is consistent with that obtained from a threshold measurement. The angular distribution of the K+K- decay pair shows that near threshold the phi-mesons are dominantly produced with polarization m=0 along the initial proton direction. No conclusive evidence for f(0)(980) production is found in the data.
Experimental studies of the near threshold production of K+K- pairs at COSY-11
D. Gil, J. Smyrski
abstract
This paper sums up experimental studies of the near threshold production of K+K- pairs at COSY-11. The total cross section of the reaction pp -> ppK(+)K(-) has been measured at five excess energies below the phi production threshold with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations.
Search for the He-4-eta bound state with WASA-at-COSY
W. Krzemien, J. Smyrski
abstract
We propose to search for the He-4 - eta bound state via measurement of the excitation functions for the dd -> (3)Hp pi(0), (3)Hn pi(+), (3)Hen pi(0),(3)Hep pi(-) reactions where the outgoing N - pi pairs originate from the conversion of the eta meson on a nucleon inside the He-4 nucleus. Precise determination of the profile of the expected Breit-Wigner distribution in the excitation curves will allow to determine the binding energy and the width of the He-4 - eta bound state.
Muon decay: Measurement of the transverse e(+) polarization and its implications on G(F) and time reversal invariance
W. Fetscher, K. Bodek, N. Danneberg, L. Jarczyk, K. Kirch, S. Kistryn, K. Kohler, J. Lang, A. Kozela, T. Schweizer, J. Smyrski, E. Stephan, A. Strzalkowski, A. von Allmen, J. Zejma
abstract
The transverse polarization components of the e(+) from the decay of polarized mu(+) have been measured at the Paul Scherrer Institute by annihilating in flight the decay positrons with polarized electrons. The use of a stroboscopic method greatly reduces systematic errors. The energy dependence of the transverse polarization component P-T1, which lies in the plane defined by muon spin and positron momentum, yields the low energy parameter eta = (-2 +/- 8) X 10(-3) and thus an improved model-independent value of the Fermi coupling constant. For the transverse polarization P-T2, averaged over the positron energy, we obtain (P-T2) = (-4 +/- 8) x 10(-3). This improves the previous limit on the violation of time invariance in muon decay [1] by a factor of three.
Study of the He-3-eta interaction
J. Smyrski
abstract
We present a summary of measurements of the dp -> (HeX)-He-3,(X = pi(0), eta) reactions performed with the COSY-11 facility. Our results for the dp -> He-3 eta total cross sections confirm a strong enhancement observed in previous experiments close to the kinematical threshold. The forward-backward asymmetries of the differential cross sections deviate clearly from zero for center of mass momenta above 50 MeV/c indicating the presence of higher partial waves in the final state. The excitation function for the reaction dp -> He-3 pi(0) does not show any structure which could originate from the decay of the He-3 - eta bound state. Our measurements do not confirm the cusp structure observed in the threshold excitation curve measured with the SPES-4 spectrometer in the vicinity of the eta production threshold.
Threshold hyperon production in proton-proton collisions at COSY-11
T. Rozek, D. Grzonka, HH. Adam, A. Budzanowski, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Kowina, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, Z. Zhang, W. Zipper
abstract
The Sigma(+) hyperon production was measured at the COSY-11 spectrometer via the pp -> nK(+)Sigma(+) reaction at excess energies of Q = 13 MeV and Q = 60 MeV. These measurements continue systematic hyperon production studies via the pp -> pK(+)Lambda/Sigma(0) reactions where a strong decrease of the cross section ratio close-to-threshold was observed. In order to verify models developed for the description of the Lambda and Sigma(0) production we have performed the measurement on the Sigma(+) hyperon and found unexpectedly that the total cross section is by more than one order of magnitude larger than predicted by all anticipated models. After the reconstruction of the kaon and neutron four momenta, the Sigma(+) is identified via the missing mass technique. Details of the method and the measurement will be given and discussed in view of theoretical models. (c) 2006 Elsevier B.V. All rights reserved.
Study of the He-3-eta system in d-p collisions at COSY-11
J. Smyrski, HH. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, A. Heczko, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, A. Taschner, P. Winter, M. Wolke, P. Wustner, Z. Zhang, W. Zipper
abstract
We present preliminary results from dp -> He-3 X, (X = pi(0),eta) measurements near the eta production threshold. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target. The He-3 ejectiles were registered with the COSY-11 detection setup. The ongoing data analysis should deliver high precision data for the dp -> He-3 eta total and differential cross sections for the excess energies in the range from threshold up to 9 MeV. The preliminary excitation function for the reaction dp -> 3 He pi(0) does not show any structure which Could originate from the decay of He-3 - eta bound state. We present also a threshold excitation curve for the dp - He-3 X channel. Contrary to corresponding results from SATURNE we see no cusp in the vicinity of the eta threshold.
The analyzing power for the (p)over-right-arrowp -> pp eta reaction at Q=10 MeV
R. Czyzykiewicz, P. Moskal, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, H. Rohdjess, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, K. Ulbrich, P. Winter, M. Wolke, P. Wustner, Z. Zhang, W. Zipper
abstract
The analyzing power A(y) for the (p) over right arrowp -> pp eta reaction has been determined at the beam momentum p(beam) = 2010 MeV/c, corresponding to the excess energy Q = 10 MeV. In the paper the method of the data analysis is briefly presented.
The Analysing power for the polarized-p p ---> p p eta reaction at Q=10MeV
R. Czyzykiewicz, P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, H. Rohdjess, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, K. Ulbrich, P. Winter, M. Wolke, P. Wuestner, Z. Zhang, W. Zipper
abstract
The analyzing power A_y for the p(pol)p --> pp eta reaction has been determined at the beam momentum p_{beam}=2010 MeV/c, corresponding to the excess energy Q=10 MeV. In the paper the method of the data analysis is briefly presented.
Study of the He-3 - eta system in d-p collisions at COSY-11
J. Smyrski, H.-H. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, A. Heczko, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, Z. Zhang, W. Zipper
abstract
We present preliminary results from dp --> 3He X (X=pi0,eta) measurements near the eta production threshold. The data were taken during a slow ramping of the COSY internal deuteron beam scattered on a proton target. The 3He ejectiles were registered with the COSY-11 detection setup. The ongoing data analysis should deliver high precision data for the dp --> 3He eta total and differential cross sections for the excess energies in the range from threshold up to 9 MeV. The preliminary excitation function for the reaction dp --> 3He pi0 does not show any structure which could originate from the decay of 3He-eta bound state. We present also a threshold excitation curve for the dp --> 3He X channel. Contrary to corresponding results from SATURNE we see no cusp in the vicinity of the eta threshold.
Correlation femtoscopy for studying eta meson production mechanism
P. Klaja, P. Moskal, H.-H. Adam, A. Budzanowski, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, J. Majewski, W. Migdal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, P. Winter, M. Wolke, P. Wuestner, Z. Zhang, W. Zipper
abstract
The high statistics data from the pp -> ppeta reaction measurement, delivered by the COSY-11 collaboration, are now being evaluated using the correlation femtoscopy technique. This method is based on the relative momentum correlations of two emitted protons and may permit determination of the size of the reaction volume. For the very first time, we apply an intensity interferometry technique to study the mechanism of the meson production via the nucleon-nucleon interaction close to the kinematical threshold. We invented a method to determine correlation function for the ppeta system free from the physical multi-pion production background. We show the comparison of experimental results with theoretical predictions and appraise the accuracy achieved for the determination of the size of the emission source.
Kaon pair production close to threshold
P. Winter, M. Wolke, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Slemaszko, J. Smyrski, A. Taschner, P. Wustner, Z. Zhang, W. Zipper
abstract
The total cross section of the reaction pp -> ppK(+)K(-) has been measured at excess energies Q = 10 MeV and 28 MeV with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations or calculations within a one boson exchange model. In addition, we present invariant mass spectra of two particle subsystems. While the K+K- system is rather constant for different invariant masses, there is an enhancement in the pK(-) system towards lower masses which could at least be partially connected to the influence of the Lambda (1405) resonance. (c) 2006 Elsevier B.V. All rights reserved.
Threshold hyperon production in proton-proton collisions at COSY-11
T. Rozek, D. Grzonka, H.-H. Adam, A. Budzanowski, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Kowina, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, Z. Zhang, W. Zipper
abstract
Sigma+ hyperon production was measured at the COSY-11 spectrometer via the p p --> n K+ Sigma+ reaction at excess energies of Q = 13 MeV and Q = 60 MeV. These measurements continue systematic hyperon production studies via the p p --> p K+ Lambda/Sigma0 reactions where a strong decrease of the cross section ratio close-to-threshold was observed. In order to verify models developed for the description of the Lambda and Sigma0 production we have performed the measurement on the Sigma+ hyperon and found unexpectedly that the total cross section is by more than one order of magnitude larger than predicted by all anticipated models.
After the reconstruction of the kaon and neutron four momenta, the Sigma+ is identified via the missing mass technique. Details of the method and the measurement will be given and discussed in view of theoretical models.
Kaon pair production close to threshold
P. Winter, M. Wolke, H.-H. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Wustner, Z. Zhang, W. Zipper
abstract
The total cross section of the reaction pp->ppK+K- has been measured at excess energies Q=10 MeV and 28 MeV with the magnetic spectrometer COSY-11. The new data show a significant enhancement of the total cross section compared to pure phase space expectations or calculations within a one boson exchange model. In addition, we present invariant mass spectra of two particle subsystems. While the K+K- system is rather constant for different invariant masses, there is an enhancement in the pK- system towards lower masses which could at least be partially connected to the influence of the Lambda(1405) resonance.
A method to disentangle single- and multi-meson production in missing mass spectra from quasi-free pn ---> pn X reactions
P. Moskal, H.-H. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, P. Klaja, A. Khoukaz, K. Kilian, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taeschner, J. Wessels, P. Winter, M. Wolke, P. Wuestner, Z. Zhang, W. Zipper
abstract
The separation of contributions from multi- and single-meson production in the missing mass spectrum of the quasi-free pn --> pnX reaction constitutes a~challenging task when the reaction is studied close to threshold. This is especially true if the resolution of the mass determination is comparable with the excess energy and if the investigated signal appears close to the kinematical limit. In this article we outline a method which permits the extraction of the signal originating from the creation of a single meson without the necessity of conducting model-dependent simulations. For the pd --> pnXp(spectator) reactions, the method allows one to combine events corresponding to multi-meson production at various excess energies with respect to the pn --> pn meson process, and hence leads to an increase of the statistics needed for the determination of the shape of the multi-meson background.
As an example of the application of the method, we demonstrate that the evaluation of the data from the pd --> pnXp(sp) process according to the described technique enables one to extract a signal of the pn --> pn eta reaction whose shape is consistent with expectations, supporting the correctness and usefulness of the method introduced.
Muon decay: Measurement of the transverse e(+) polarization and its implications on G(F) and time reversal invariance
W. Fetscher, K. Bodek, N. Danneberg, L. Jarczyk, K. Kirch, S. Kistryn, K. Kohler, J. Lang, A. Kozela, T. Schweizer, J. Smyrski, E. Stephan, A. Strzalkowski, A. von Allmen, J. Zejma
abstract
The transverse polarization components of the positrons from the decay of polarized muons have been measured at the Paul Scherrer Institute by annihilating in flight the decay positrons with polarized electrons. The use of a stroboscopic method greatly reduces systematic errors. The energy dependence of the transverse polarization component P-TI, which lies in the plane defined by muon spin and positron momentum, yields the low energy parameter eta = (-2 +/- 8) x 10(-3) and thus an improved model-independent value of the Fermi coupling constant. For the transverse polarization P-T2, averaged over the positron energy, we obtain (P-T2) = (-4 +/- 8) x 10(-3). This improves the previous limit on the violation of time invariance in muon decay [1] by a factor of three.
Measurement of the transverse e(+) polarization from the decay of polarized mu(+) and its implications on G(F) and time reversal invariance
W. Fetscher, K. Bodek, N. Danneberg, L. Jarczyk, S. Kistryn, K. Kohler, K. Kirch, A. Kozela, J. Lang, J. Smyrski, T. Schweizer, E. Stephan, A. Strzalkowski, J. Zejma, A. von Allmen
abstract
The transverse polarization of the e(+) from the decay of polarized mu(+) has been measured at the Paul Scherrer Institute. From the energy dependence of the transverse polarization component P-T1, which lies in the plane spanned by muon spin and positron momentum, the decay parameters mu and mu '' are derived, the first of which yields an improved model-independent value of the Fermi coupling constant. A non-zero value of the transverse component P-T2, which is perpendicular to the plane mentioned above, would be the first observation of time reversal violation in a purely leptonic decay. From the energy dependence of P-T2 the two decay parameters alpha'/A and beta'/A are deduced. Part of the data (40 x 10(8) annihilation events) have been evaluated. Both P-T1 and P-T2 averaged over the positrons' energy, are consistent with zero in full agreement with the standard model. The precision obtained is Delta < P-T1> = Delta < P-T2> = 8 x 10(-3). which is an improvement by a factor of three as compared to the results of the previous experiment [1].
Hadronic interaction of the 77 meson with two nucleons
P. Moskal, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
The COSY-11 collaboration has conducted experiments aiming at the determination of the excitation function and phase-space population of the pp -> pp eta reaction close to the kinematical threshold. The precise data obtained with the stochastically cooled proton beam of the cooler synchrotron COSY and the high resolution zero-degree magnetic spectrometer allowed for the observation of the significant deviations - in the shape of the excitation function and two-particle invariant masses - from the predictions based on the assumption that the reaction phase space is homogenously populated. Comparison of the shape of the excitation function for the pp -> pp eta and pp -> pp eta' reaction allows to distinquish in the model independent way an influence originating from the protonproton and proton-eta interaction. For the comparison the full data set from experiments performed at COSY and other laboratories is used.
Antiproton physics at GSI with PANDA
J. Smyrski
abstract
Detector PANDA was proposed for studies of the interaction of antiprotons with nucleons and nuclei at the future GSI accelerator facility. Selected topics of physics program at PANDA including studies of the interaction of charmed hadrons in matter, production of double A-hypernuclei, CP-violation in the D (D) over bar and Lambda$(Lambda) over bar $ system as well as studies of electromagnetic form factors of proton are presented.
Search for Bremsstrahlung radiation in quasi-free np -> np gamma reactions
J. Przerwa, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, N. Lang, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Due to the high sensitivity of the NN -> NN gamma reaction to the nucleon-nucleon potential, Bremsstrahlung radiation is used as a tool to investigate details of the nucleon-nucleon interaction. Such investigations can be performed at the cooler synchrotron COSY in the Research Centre Julich, by dint of the COSY-11 detection system. The results of the identification of Bremsstrahlung radiation emitted via the dp -> dp gamma reaction in data taken with a proton target and a deuteron beam are presented and discussed.
Threshold hyperon production at COSY-11
T. Rozek, D. Grzonka, K. Kilian, P. Kowina, W. Oelert, T. Sefzick, P. Winter, M. Wolke, P. Wustner, M. Siemaszko, W. Zipper, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, J. Smyrski, HH. Adam, A. Khoukaz, R. Santo, A. Taschner, A. Budzanowski
abstract
The Lambda, Sigma(0) and Sigma(+) hyperon production in NN collisions is studied at the COSY - 11 installation in order to investigate the production mechanism as well as to extract information about the Y-N interaction.
Production of eta mesons in proton-proton collisions close to threshold
R. Czyzykiewicz, HH. Adam, A. Budzanowski, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Kowina, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
A brief experimental overview on the close-to-threshold eta meson production in proton-proton interactions is presented and the available observables in measurements with unpolarized and polarized beam and target are discussed.
New results on the pd -> He-3 eta production near threshold
HH. Adam, A. Khoukaz, N. Lang, T. Lister, R. Santo, S. Steltenkamp, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, J. Smyrski, D. Grzonka, K. Kilian, W. Oelert, T. Sefzick, P. Winter, M. Wolke, P. Wustner, A. Budzanowski, T. Rozek, M. Siemaszko, W. Zipper
abstract
Measurements on the eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Julich). Here we present preliminary results on total and differential cross sections for the pd -> He-3 eta reaction at five excess energies between Q = 5.1 and Q = 40.6 MeV. The obtained angular distributions for the emitted eta mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong eta-He-3 final state interaction and will be compared with model predictions.
Muon decay: Measurement of the transverse polarization of the decay positrons and its implications for the Fermi coupling constant and time reversal invariance
N. Danneberg, W. Fetscher, KU. Kohler, J. Lang, T. Schweizer, A. von Allmen, K. Bodek, L. Jarczyk, S. Kistryn, J. Smyrski, A. Strzalkowski, J. Zejma, K. Kirch, A. Kozela, E. Stephan
abstract
The two transverse polarization components P-T1 and P-T2 of the e(+) from the decay of polarized mu(+) have been measured as a function of the e(+) energy. Their energy averaged values are
=(6.3+/-7.7+/-3.4)x10(-3) and =(-3.7+/-7.7+/-3.4)x10(-3). From the energy dependence of P-T1 and P-T2 the decay parameters eta,eta('') and alpha(')/A,beta(')/A are derived, respectively. Assuming only one additional coupling besides the dominant V-A interaction one gets improved limits on eta, beta(')/A, and the scalar coupling constant g(RR)(S): eta=(-2.1+/-7.0+/-1.0)x10(-3), beta(')/A=(-1.3+/-3.5+/-0.6)x10(-3), Re{g(RR)(S)}=(-4.2+/-14.0+/-2.0)x10(-3), and Im{g(RR)(S)}=(5.2+/-14.0+/-2.4)x10(-3).Drift chamber with a c-shaped frame
J. Smyrski, Ch. Kolf, H.-H. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, A. Heczko, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, A. Misiak, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, C. Quentmeier, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
We present the construction of a planar drift chamber with wires stretched between two arms of a c-shaped aluminium frame. The special shape of the frame allows to extendthe momentum acceptance of the COSY-11 detection system towards lower momenta without suppressing the high momentum particles. The proposed design allows for construction of tracking detectors covering small angles with respect to the beam, which can be installed and removed without dismounting the beam-pipe. For a three-dimensional track reconstruction a computer code was developed using a simple algorithm of hit preselection.
New results on pd -> He-3 eta production from threshold up to Q=40 MeV
HH. Adam, A. Khoukaz, N. Lang, T. Lister, R. Santo, S. Steltenkamp, R. Czyzykiewicz, M. Janusz, L. Jarczyk, B. Kamys, P. Klaja, P. Moskal, C. Piskor-Ignatowicz, J. Przerwa, J. Smyrski, D. Grzonka, K. Kilian, W. Oelert, T. Sefzick, P. Winter, M. Wolke, P. Wustner, A. Budzanowski, T. Rozek, M. Siemaszko, W. Zipper
abstract
Measurements on the eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Julich). Here we present preliminary results on total and differential cross sections for the pd -> He-3 eta reaction at five excess energies between Q = 5.1 and Q = 40.6 MeV. The obtained angular distributions for the emitted eta mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong eta-He-3 final state interaction and will be compared with model predictions.
Isospin dependence of the eta' meson production in nucleon-nucleon collisions
J. Przerwa, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, J. Wessels, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
According to the quark model, the masses of eta and eta' mesons should be almost equal. However, the empirical values of these masses differ by more than a factor of two. Similarly, though they have almost the same quark-antiquark content, the total cross section for the creation of these mesons close to the kinematical thresholds in the pp -> ppX reaction differs significantly. Using the COSY-11 detection setup we intend to determine whether this difference will also be so significant in the case of the production of these mesons in the proton-neutron scattering. Additionally, the comparison of the pp -> pp eta' and pn -> pn eta' total cross sections will allow to learn about the production of the eta' meson in the channels of isospin 1 = 0 and 1 = 1 and to investigate aspects of the gluonium component of the eta' meson.
Energy dependence of the Lambda/Sigma(0) production cross-section ratio in p-p interactions
P. Kowina, M. Wolke, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, J. Haidenbauer, M. Janusz, L. Jarczyk, A. Khoukaz, K. Kilian, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, C. Quentmeier, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, P. Winter, P. Wustner, W. Zipper
abstract
The production of the Lambda- and Sigma(0)-hyperous has been measured via the pp --> pK(+)Lambda/Sigma(0) reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the Lambda/Sigma(o) cross-section ratio from about 28 at Q less than or equal to 13 MeV to the high-energy level of about 2.5 is covered by the data showing a strong decrease of the ratio between 10 and 20 MeV excess energy. Effects from the final-state interactions in the p-Sigma(o) channel seem to be much smaller than in the p-A channel. Estimates of the effective range parameters are given for the NLambda and the NSigma systems.
Total and differential cross-sections for the pp -> pp eta ' reaction near threshold
A. Khoukaz, I. Geck, C. Quentmeier, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, L. Jarczyk, K. Kilian, P. Kowina, N. Lang, T. Lister, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, T. Rozek, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, A. Strzalkowski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
The eta'-meson production in the reaction pp --> ppeta' has been studied at excess energies of Q = 26.5, 32.5 and 46.6 MeV using the internal beam facility COSY-11 at the cooler synchrotron COSY. The total cross-sections as well as one angular distribution for the highest Q-value are presented. The excitation function of the near-threshold data can be described by a pure s-wave phase space distribution with the inclusion of the proton-proton final-state interaction and Coulomb effects. The obtained angular distribution of the eta'-mesons is also consistent with pure s-wave production.
Experimental study of pp eta dynamics in the pp -> pp eta reaction
P. Moskal, ..., H.-H. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, M. Siemaszko, J. Smyrski et al.
abstract
A high statistics measurement of the pp --> ppeta reaction at an excess energy of Q = 15.5 MeV has been performed at the internal beam facility COSY-11. The stochastically cooled proton beam and the used detection system allowed to determine the momenta of the outgoing protons with a precision of 4 MeV/c (sigma) in the center-of-mass frame. The determination of the four-momentum vectors of both outgoing protons allowed to derive the complete kinematical information of the ppeta-system.
An unexpectedly large enhancement of the occupation density in the kinematical regions of low proton-eta relative momenta is observed. A description taking the proton-proton and the eta-proton interaction into account and assuming an on-shell incoherent pairwise interaction among the produced particles fails to explain this strong effect. Its understanding will require a rigorous three-body approach to the ppeta system and the precise determination of contributions from higher partial waves.
We also present an invariant mass spectrum of the proton-proton system determined at Q = 4.5 MeV. Interestingly, the enhancement at large relative momenta between protons is visible also at such a small excess energy.
In contrast to all other determined angular distributions, the orientation of the emission plane with respect to the beam direction is extracted to be anisotropic.
Isospin symmetry breaking as a tool for particle physics investigations
A. Magiera, S. Abdel-Bary, P. Hawranek, J. Ilieva, K. Kilian, D. Kirilov, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, G. Martinska, L. Pentchev, N. Piskunov, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, J. Smyrski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
The importance of the isospin symmetry breaking in extracting various particle physics parameters is discussed. In particular the measurement of isospin symmetry breaking in the reaction pd --> (3)Hpi(+)/(3)Hepi(0) is presented. The energy dependence of the measured cross sections ratio indicate isospin symmetry breaking effects. Within a simple model based on pi(0) - eta meson mixing the mixing angle of these mesons is extracted.
Production of eta and eta ' mesons via the quasi-free proton-neutron interaction
P. Moskal, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, A. Strzalkowski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
A comparison of the close-to-threshold total cross sections for the eta' meson production in both the pp --> ppeta' and pn --> pneta' reactions should provide insight into the flavour-singlet (perhaps also into gluonium) content of the eta' meson and the relevance of quark-gluon or hadronic degrees of freedom in the creation process. The excitation function for the reaction pp --> ppeta' has been already established. At present, experimental investigations of the quasi-free pn --> pnX reactions are carried out at the COSY-11 facility using a beam of stochastically cooled protons and the deuteron cluster target. A method of measurement and preliminary results from the test experiments of the pn --> pneta reaction are presented in this report.
Measurement of the transverse polarization of the e(+) from the decay of polarized mu(+)
W. Fetscher, K. Bodek, A. Budzanowski, N. Danneberg, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, K. Kohler, J. Lang, A. Kozela, J. Smyrski, E. Stephan, A. Strzalkowski, A. von Allmen, J. Zejma
abstract
The transverse polarization components of the positrons from the decay of polarized muons have been measured at the Paul Scherrer Institute by annihilating in flight the decay positrons with polarized electrons. The use of a stroboscopic method greatly reduces systematic errors. The energy dependence of the transverse polarization component P-T1, which lies in the plane spanned by muon spin and positron momentum, yields the low energy parameter eta and thus an improved model-independent value of the Fermi coupling constant. A non-zero value of the transverse component P-T2, which is perpendicular to the plane mentioned above, would be the first observation of time reversal violation in a purely leptonic decay. Part of the data (40 x 10(8) annihilation events) have been evaluated. Both P-T1 and P-T2, averaged over the positrons' energy, are consistent with zero with a precision improved by a factor of three as compared with the previous measurement [1]. The preliminary results are
= (7 +/- 8) x 10(-3), = (-1 +/- 8) x 10(-3) in full agreement with the standard model.Energy dependence of the Lambda/Sigma(0) production cross section ratio in p-p interactions.
P. Kowina, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Measurements of the near threshold Lambda and Sigma(0) production via the pp --> pK(+)Lambda/Sigma(0) reaction at COSY-11 have shown that the Lambda/Sigma(0) cross section ratio exceeds the value at high excess energies (Q greater than or equal to 300 MeV) by an order of magnitude. For a better understanding additional data have been taken between 13 MeV and 60 MeV excess energy. Within the first 20 MeV excess energy a strong decrease of the cross section ratio is observed, with a less steep decrease in the higher excess energy range. A description of the data with a parametrisation including p - Y final state interactions suggests a much smaller p - Sigma(0) FSI compared to the p - Lambda system.
Analysis of the eta meson production mechanism via the (p)over-barp -> pp eta reaction
R. Czyzykiewicz, HH. Adam, A. Budzanowski, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, P. Wustner, W. Zipper
abstract
Polarisation observables constitute a powerful tool for establishing the production mechanism of the eta meson and for infering the presence of higher partial waves in the final system. Measurements of the proton analysing power for the (p) over right arrowp --> ppeta reaction have been performed by the COSY-11 group at three different excess energies: Q = 10, 37 and 40 MeV. Data at Q = 40 MeV indicate that the eta meson is probably produced in partial waves higher than s wave.
Associated strangeness production at threshold
P. Kowina, M. Wolke, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, T. Lister, P. Moskal, W. Oelert, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, P. Winter, P. Wustner, W. Zipper
abstract
The associated strangeness dissociation at threshold has been studied at the COSY-11 facility measuring the hyperon and the K (+) K(-) meson pair production. Measurements of the near-threshold Lambda and Sigma(o) production via the pp --> pK(+) Lambda/Sigma(0) reaction (S. Sewerinet al., Phys. Rev. Lett. 83, 682 (1999)) at COSY-11 have shown that the Lambda/Sigma(o) cross-section ratio exceeds the value at high excess energies (Q greater than or equal to 300 MeV (A. Baldiniet al., Total Cross-Sections for Reactions of High-Energy Particles, Landolt-Bornstein, New Series, Vol. I/12 (Springer, Berlin, 1988))) by an order of magnitude. For a better understanding additional data have been taken between 13 MeV and 60 MeV excess energy. The near-threshold production of the charged kaon-antikaon pair is related to the discussion about the nature of the scalar states in the 1 GeV/c(2) mass range, i.e. the f(0)(980) and a(0)(980) (O. Krehl, R. Rapp, J. Speth, Phys. Lett. B 390, 23 (1997)). The interpretation as a K (K) over bar molecule is strongly dependent on the K-(K) over bar interaction which can be studied via the production channel. A first total cross-section value on the reaction pp --> pp K(+) K(-) at an excess energy of 17 MeV (C. Quentmeieret al., Phys. Lett. B 515, 276 (2001)), i.e. below the phi production threshold, was measured.
First close-to-threshold measurement of the analysing power A(y) in the reaction (p)over-right-arrowp -> pp eta
P. Winter, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, T. Lister, P. Moskal, W. Oelert, C. Piskor-Ignatowicz, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, A. Taschner, M. Wolke, P. Wustner, W. Zipper
abstract
At the internal facility COSY-11 a first measurement of the reaction (p) over right arrowp --> ppeta near the production threshold has been performed. Results for the analysing power will be presented and a comparison with one-meson exchange models will be discussed.
Upper limit for the cross-section of the overlapping scalar resonances f(0)(980) and a(0)(980) produced in proton-proton collisions in the range of the reaction threshold
P. Moskal, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, C. Kolf, P. Kowina, T. Lister, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, C. Quentmeier, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, A. Strzalkowski, A. Taschner, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Utilizing a missing mass technique we investigate the pp --> ppX reaction scanning beam energies in the range permitting to create a mass close to that of the f(0) (980) and a(0) (980) scalar resonances, but still below the K+ K- threshold where they decay dominantly into pi pi and pi eta mesons, respectively. Prior to the data analysis we introduce a notion of the close to threshold total cross-section for broad resonances. We estimated for the overlapping mesons a(0) and f(0) the total cross-section to be smaller than 430 nb at excess energy of Q = 5 MeV. The experiment has been performed at the Cooler Synchrotron (COSY) using the COSY-11 facility.
Measurement of the polarization vector of the e(+) from the decay of polarized mu(+) as a test of time reversal invariance
W. Fetscher, K. Bodek, A. Budzanowski, N. Danneberg, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, GL. Llacer, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
The complete polarization vector of the positrons from the decay of polarized muons has been measured for the first time with one experimental setup. The mu(pT) experiment at the Paul Scherrer Institute determines the three polarization components simultaneously with the same apparatus by making use of three different effects (spatial and temporal dependence of annihilation-in-flight with polarized electrons as well as muon decay asymmetry). The use of a stroboscopic method greatly reduces systematic errors. The energy dependence of the transverse polarization component P-T1, which lies in the plane spanned by muon spin and positron momentum, yields the low energy parameter eta and thus an improved model-independent value of the Fermi coupling constant. A non-zero value of the transverse component P-T2, which is perpendicular to the above-mentioned plane, would be the first observation of time reversal violation in a purely leptonic decay. The preliminary results are P-T1=(5+/-16)x10(-3), P-T2=(1+/-16)x10(-3) and P-L=(1.09+/-0.15).
pi(0)-eta meson mixing in pd -> H-3 pi(+)/He-3 pi(0) reactions
M. Abdel-Bary, P. Hawranek, J. Ilieva, K. Kilian, D. Kirilov, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, L. Pentchev, N. Piskunov, P. von Rossen, BJ. Roy, I. Sitnik, R. Siudak, J. Smyrski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
Beam momentum dependence of the experimental cross sections for pd-->(3)Hpi(+)/(3)Hepi(0) reactions have been studied at large proton-pion relative angle. The measurements were performed for five beam momenta in the region of the eta meson production threshold. Observed behavior of the measured cross sections ratio reveals manifestations of the isospin symmetry breaking effects. A simple model allows one to interpret the isospin symmetry breaking in terms of pi(0)-eta meson mixing. Based on that model analysis of the experimental results leads to the mixing angle value of 0.006+/-0.005 rad.
Polarized Muon decay: Measurement of the polarization vector of the decay positrons as a test of time reversal invariance
W. Fetscher, K. Bodek, A. Budzanowski, N. Danneberg, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, X. Morelle, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
The mu(PT) experiment at the Paul Scherrer Institut has determined the three polarization components of positrons from polarized muon decay simultaneously with the same apparatus by making use of three different effects (spatial and temporal dependence of annihilation-in-flight with polarized electrons and muon decay asymmetry). The use of a stroboscopic method greatly reduces systematic errors. The energy dependence of the transverse polarization component P-T1, which lies in the plane spanned by muon-spin and positron momentum, yields the low energy parameter eta and thus an improved model-independent value of the Fermi coupling constant. A non-zero value of the transverse component P-T2, which is perpendicular to the above mentioned plane, would be the first observation of time reversal violation in a purely leptonic decay. The preliminary results are P-T1 = (5 +/- 16) X 10(-3), p(T2) = (1 +/- 16) x 10(-3) and P-L = 1.09 +/- 0.15.
Hadronic interaction of eta and eta ' mesons with nucleons
P. Moskal, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, T. Lister, W. Oelert, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
Due to their short life-time, flavour-neutral mesons cannot be utilized as free secondary beams or targets, and therefore a study of their interaction with nucleons is not possible via direct scattering experiments. It is, however, accessible via its influence on the energy dependence - and on the phase space distributions of the cross sections for reactions in which these mesons are produced. In case of the pp --> ppeta reaction the experimentally determined distributions of the differential cross sections close to the production threshold cannot be described by taking into account the S-wave proton-proton and proton-eta interaction only. Here we show that the angular distributions determined at the COSY-11 facility reveal some evidence for P-wave admixture in the proton-proton subsystem already at an excess energy as low as Q = 15.5 MeV. We also present that one can estimate the relative strength of the eta-nucleon and eta'-nucleon interactions by comparison of the eta and eta' production yield.
Strangeness production in proton-proton collisions close to threshold
M. Wolke, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Kowina, T. Lister, P. Moskal, W. Oelert, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, P. Winter, P. Wustner, W. Zipper
abstract
Exclusive data on the reactions pp --> ppK(+)K(-) and pp --> pK(+Lambda)/Sigma(0) have been taken at the cooler synchrotron COSY close to threshold. At equal excess energies, an enhancement of the Lambda/Sigma(0) ratio by one order of magnitude has been observed compared to data at higher excess energies. New results obtained at the COSY-11 facility explore the transition region between this low-energy Sigma(0) suppression and excess energies of 60 MeV. A first total cross section for elementary antikaon production below the phi threshold has been determined, two orders of magnitude smaller compared to kaon production at the same excess energy.
Determination of the polarization of the decay positrons in polarized muon decay
KU. Kohler, K. Bodek, A. Budzanowski, N. Danneberg, W. Fetscher, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, A. Kozela, J. Lang, GL. Llacer, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
The standard model of electroweak interactions predicts that the positrons from the decay of polarized positive muons are mainly longitudinally polarized. The measurement of the two transverse polarization components of the positron P-T1 and P-T2 is a sensitive tool to look for contributions from additional, exotic interactions and for the violation of time reversal invariance in this purely leptonic decay. The mu(PT)-experiment at the Paul Scherrer Institute determines the three positron polarization components simultaneously with the same apparatus by making use of three different effects. By examining the temporal dependence of annihilation-in-flight of the decay positrons with polarized electrons a possible non-zero value of the transverse polarization is determined. The phase of this transverse polarization can be measured by making use of the decay asymmetry. Using the dependence of annihilation-in-flight on the angle between electron polarization and positron momentum leads to the determination of the longitudinal polarization which not only completes the measurement of the entire polarization vector but also serves as a sensitivity check. In order to deduce the polarization at the time and location of the muon decay a method based on Monte-Carlo simulations with full spin-dependence implemented is being developed.
Study of the eta proton interaction via the reaction p p -> p p eta
P. Moskal, ..., H.H. Adam, A. Budzanowski, R. Czyzykiewicz, T. Gotz, D. Grzonka, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, et al.
abstract
PiN Newslett. 16 (2002) 367-369
A measurement of the pp --> p p eta reaction at the excess energy of Q = 15.5 +- 0.4 MeV has been carried out at the internal beam facility COSY-11 with an integrated luminosity of 811 nb^-1 The number of ~24000 identified events permits a precise determination of total (2.32 +- 0.05 +- 0.35 mu b) and differential cross sections. Preliminary investigations show that the angular distribution of the eta meson in the center-of-mass system is isotropic. A qualitative analysis of the Dalitz-plot distribution is presented.
Analysing power A y in the reaction (p)over-right-arrowp -> pp eta close to threshold
P. Winter, HH. Adam, F. Bauer, A. Budzanowski, R. Czyzykiewicz, T. Gotz, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian, C. Kolf, P. Kowina, N. Lang, T. Lister, P. Moskal, W. Oelert, C. Quentmeier, T. Rozek, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, M. Wolke, P. Wustner, W. Zipper
abstract
Measurements of the eta meson production with a polarised proton beam in the reaction (p) over barp --> ppeta have been carried out at an excess energy of Q = 40 MeV. The dependence of the analysing power A,. on the polar angle theta(q)(*) of the 17 meson in the q center of mass system (CMS) has been studied. The data indicate the possibility of an influence of p- and d-waves to the close to threshold 17 production. (C) 2002 Elsevier Science B.V. All rights reserved.
Magnetic spectrometer Big Karl for studies of meson production reactions
J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, P. Hawranek, J. Ilieva, L. Jarczyk, K. Kilian, S. Kistryn, S. Kliczewski, W. Klimala, D. Kolev, M. Kravcikova, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, G. Martinska, L. Pentchev, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, M. Ulicny, J. Urban, A. Wronska
abstract
The paper describes modifications of the Julich magnetic spectrometer Big Karl needed to study meson production and especially to investigate charge symmetry breaking effects-an experiment that requires a high-precision measurement. New elements that have been added to Big Karl have extended the spectrometer capabilities to a much wider momentum range. The new features also facilitate simultaneous detection of particles with very different rigidities. The experimental methods for improving background and determining relative acceptance of the spectrometer at various rigidities are presented. (C) 2001 Elsevier Science B.V. All rights reserved.
Experimental results on strangeness production in proton-proton collisions at COSY
P. Moskal, HH. Adam, A. Budzanowski, R. Czyzykiewicz, D. Grzonka, C. Kolf, L. Jarczyk, A. Khoukaz, K. Kilian, P. Kowina, N. Lang, T. Lister, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, A. Strzalkowski, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
The production of K+ and K- mesons in elementary proton-proton collisions has been investigated at the Cooler synchrotron COSY in Julich. A high quality proton beam with low emittance and small momentum spread permitted study of the creation of these mesons very close to the kinematical threshold. The energy dependence of the total cross section is investigated using internal beam facilities providing a high accuracy particle momentum determination as well as an external non-magnetic detection setup with a large geometrical acceptance. The determination of the four-momentum vectors for all ejectiles of each registered event gives the complete kinematical information allowing study of the interaction of the outgoing particles. Results on the performed studies of the pp --> ppK(+)K(-), pp --> pLambdaK(+) and pp --> pSigma(0)K(+) reactions will be presented and their relevance to the interpretation of heavy ion collisions will be discussed.
Recent results from the COSY-11 experiment on near-threshold meson production in pp and pd collisions
J. Smyrski, HH. Adam, A. Budzanowski, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian, C. Kolf, P. Kowina, N. Lang, T. Lister, P. Moskal, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, A. Strzalkowski, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
The near-threshold production of K+K- pairs, as well as of eta mesons, has been measured in proton-proton collisions using the COSY-11 facility at the cooler synchrotron COSY. The obtained cross section for the pp --> ppK(+)K(-) reaction at an excess energy of Q = 17 MeV represents the first measurement on the K+K- production below the Phi meson production threshold. The possible influence of a resonant production via intermediate scalar states f(0)(980) and a(0)(980) is discussed. The total cross sections for eta meson production in the pp --> ppeta reaction were determined for eight different excess energies in the range from Q = 0.5 MeV to Q = 5.4 MeV. Inclusion of the eta-proton interaction is essential for the description of the energy dependence of the total cross section. The effect of eta-proton interaction is also seen in the Dalitz plot from a high statistics measurement at Q = 15.4 MeV. The ongoing studies at the COSY-11 facility of eta meson production in the (p) over barp --> ppeta, pd --> (3)Heeta and dp --> pdeta are also presented.
On the close to threshold meson production in neutron-neutron collisions
P. Moskal, HH. Adam, A. Budzanowski, T. Gotz, D. Grzonka, L. Jarczy, A. Khoukaz, K. Kilian, C. Kolf, P. Kowina, N. Lang, T. Lister, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, M. Siemaszko, J. Smyrski, S. Steltenkamp, A. Strzalkowski, P. Winter, M. Wolke, P. Wustner, W. Zipper
abstract
A method of measuring the close to threshold meson production in neutron-neutron collisions is described where the momenta of the colliding neutrons can be determined with the accuracy obtainable for the proton-proton reaction. The technique is based on the double quasi-free nn --> nnX(0) reaction, where deuterons are used as a source of neutrons. (C) 2001 Elsevier Science B.V. All rights reserved.
Near threshold K+ K- meson-pair production in proton proton collisions
C. Quentmeier, ..., H.-H. Adam, J. T. Balewski, A. Budzanowski, D. Grzonka, P. Moskal, M. Siemaszko, J. Smyrski et al.
abstract
The near threshold total cross section and angular distributions of K+K? pair production via the reaction pp?ppK+K? have been studied at an excess energy of Q = 17?MeV using the COSY-11 facility at the cooler synchrotron COSY. The obtained cross section as well as an upper limit at an excess energy of Q = 3?MeV represent the first measurements on the K+K? production in the region of small excess energies where production via the channel pp?pp??ppK+K? is energetically forbidden.
Near threshold K+K- meson-pair production in proton-proton collisions
C. Quentmeier, HH. Adam, JT. Balewski, A. Budzanowski, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian, P. Kowina, N. Lang, T. Lister, P. Moskal, W. Oelert, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner, W. Zipper
abstract
The near threshold total cross section and angular distributions of K+K- pair production via the reaction pp --> ppK(+)K(-) have been studied at an excess energy of Q = 17 MeV using the COSY-11 facility at the cooler synchrotron COSY. The obtained cross section as well as an upper limit at an excess energy of Q = 3 MeV represent the first measurements on the K+K- production in the region of small excess energies where production via the channel pp --> pp Phi --> ppK(+)K(-) is energetically forbidden. The possible influence of a resonant production via intermediate scalar states f(0)(980) and a(0)(980) is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
New results on eta and eta ' photoproduction with SAPHIR at ELSA
J. Barth, C. Bennhold, W. Braun, J. Ernst, KH. Glander, S. Goers, J. Hannappel, N. Joepen, H. Kalinowsky, F. Klein, E. Klempt, A. Kozela, R. Lawall, J. Link, T. Mart, D. Menze, W. Neuerburg, M. Ostrick, E. Paul, H. van Pee, I. Schulday, WJ. Schwille, J. Smyrski, U. Thoma, R. Wedemeyer, B. Wiegers, FW. Wieland, J. Wisskirchen
abstract
Simultaneous measurements of the p+d -> (A=3)+pi reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
A stack of annular detectors made of high-purity germanium was used to measure simultaneously pd --> H-3 pi (+) and pd --> He-3 pi (0) differential cross sections at beam momenta of 750 MeV/c, 800 MeV/c, and 850 MeV/c over a large angular range. The extracted total cross sections for the pd --> He-3 pi (0) reactions bridge a gap between near threshold data and those in the resonance region. The ratio of the cross sections for the two reaction channels taken at the same eta = P-pi(cm) / m(pi) yields 2.11 +/- 0.08 indicating that a deviation from isospin symmetry is very small. (C) 2001 Elsevier Science B,V. All rights reserved.
Monitoring of the accelerator beam distributions for internal target facilities
P. Moskal, HH. Adam, A. Budzanowski, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian, P. Kowina, N. Lang, T. Lister, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner, W. Zipper
abstract
We describe a direct method for monitoring the geometrical dimensions of a synchrotron beam at the target position for internal target installations. The method allows for the observation of the proton beam size as well as the position of the beam relative to the target. As a first demonstration of the technique, we present results obtained by means of the COSY-11 detection system installed at the cooler synchrotron COSY. The influence of the stochastic cooling on the COSY proton beam dimensions is also investigated. (C) 2001 Elsevier Science B.V. All rights reserved.
Proton-induced deuteron breakup reaction at 65 MeV: Unspecific configurations
K. Bodek, J. Golak, L. Jarczyk, S. Kistryn, J. Kuros-Zolnierczuk, J. Lang, A. Micherdzinska, R. Skibiński, J. Smyrski, M. Sokolowski, J. Sromicki, A. Strzalkowski, H. Witała, J. Zejma, W. Zipper
abstract
Cross sections and vector-analyzing powers for four unspecific configurations of the H-2(p,pp)yl breakup reaction at E-p(lab) = 65 MeV were measured in a kinematically complete experiment. Measured observables are compared with rigorous Faddeev calculations using four realistic charge-dependent interaction models, the CD Bonn, Argonne upsilon (18), Nijmegen I, and Nijmegen II potentials with or without inclusion of the Tucson-Melbourne three-nucleon force. Coulomb effects are completely omitted. A satisfactory agreement between theory and experiment has been found. There exist, however, some discrepancies between measured and calculated analyzing-power distributions in certain kinematical regions. The effects of the Tucson-Melbourne three-body force are either negligible or slightly increasing the disagreement.
Proton-induced deuteron breakup reaction at 65 MeV: Unspecific configurations
K. Bodek, J. Golak, L. Jarczyk, S. Kistryn, J. Kuros-Zolnierczuk, J. Lang, A. Micherdzinska, R. Skibinski, J. Smyrski, M. Sokolowski, J. Sromicki, A. Strzalkowski, H. Witala, J. Zejma, W. Zipper
abstract
Cross sections and vector-analyzing powers for four unspecific configurations of the H-2(p,pp)yl breakup reaction at E-p(lab) = 65 MeV were measured in a kinematically complete experiment. Measured observables are compared with rigorous Faddeev calculations using four realistic charge-dependent interaction models, the CD Bonn, Argonne upsilon (18), Nijmegen I, and Nijmegen II potentials with or without inclusion of the Tucson-Melbourne three-nucleon force. Coulomb effects are completely omitted. A satisfactory agreement between theory and experiment has been found. There exist, however, some discrepancies between measured and calculated analyzing-power distributions in certain kinematical regions. The effects of the Tucson-Melbourne three-body force are either negligible or slightly increasing the disagreement.
Polarized muon decay: Measurement of the polarization vector of the decay positrons
K. Bodek, A. Budzanowski, N. Danneberg, W. Fetscher, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, GL. Llacer, M. Markiewicz, X. Morelle, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
In the standard model (SM) Of electroweak interactions the positron from the decay of polarized positive muons is mainly longitudinally polarized. The measurement of the two transverse polarization components, therefore, is a sensitive tool for contributions from additional, exotic, interactions. The energy dependence of the transverse polarization component P-T1, which lies in the plane spanned by muon-spin and positron momentum, yields the low energy parameter eta and thus an improved model-independent value of the Fermi coupling constant. A non-zero value of the transverse component PT2, which is perpendicular to the above mentioned plane, would be the first observation of time reversal violation in a purely leptonic decay. The mu (PT) experiment at the Paul Scherrer Institute determines the three polarization components simultaneously with the same apparatus by making use of three different reactions (spatial and temporal dependence of annihilation-in-flight with polarized electrons as well as muon decay asymmetry). The use of a stroboscopic method greatly reduces systematic errors. The measurement of the longitudinal polarization serves mainly as a test of the sensitivity of the apparatus, while the measurement of the two transverse components will improve the current experimental limits. The preliminary results are P-T1 = (7 +/- 13) x 10(-3), P-T2 = (19 +/- 13) x 10(-3).
Near threshold K+K- meson-pair production in proton-proton collisions
A. Khoukaz, C. Quentmeier, HH. Adam, JT. Balewski, A. Budzanowski, D. Grzonka, L. Jarczyk, K. Kilian, P. Kowina, N. Lang, T. Lister, P. Moskal, W. Oelert, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner, W. Zipper
abstract
The near threshold total cross section and angular distributions of K+K- pair production via the reaction pp --> ppK(+)K(-) have been studied at an excess energy of Q = 17 MeV using the COSY-I I facility at the cooler synchrotron COSY The obtained cross section as well as an upper limit at an excess energy of Q = 3 MeV represent the first measurements on the K+K- production in the region of small excess energies where production via the channel pp --> ppPhi --> ppK(+)K(-) is energetically forbidden.
An apparatus for the measurement of the transverse polarization of positrons from the decay of polarized muons
IC. Barnett, C. Bee, K. Bodek, A. Budzanowski, N. Danneberg, P. Eberhardt, W. Fetscher, C. Hilbes, M. Janousch, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, G. Llosa, M. Markiewicz, X. Morelle, O. Naviliat, T. Schweizer, J. Smyrski, J. Stromicki, E. Stephan, A. Strzalkowski, K. Szeker, J. Zejma
abstract
An apparatus for the measurement of the two transverse polarization components P-T1 and P-T2 of the positrons from polarized mu (+) decay is described. It makes use of a stroboscopic method which cancels many systematic asymmetries and allows one to use muon stop rates in the order of up to 10(8) s(-1). The experiment aims at an accuracy of DeltaP(T1) = DeltaP(T2), = 3 x 10(-3) and by that at an improvement of the existing limit by nearly one order of magnitude. With these results one will obtain an improved model-independent value for the Fermi coupling constant G(F) and more stringent limits to possible violations of time reversal invariance in a purely leptonic reaction: (C) 2000 Elsevier Science B.V. All rights reserved.
S - wave eta-prime proton FSI: Phenomenological analysis of near threshold production of pi0, eta, and eta-prime mesons in proton proton collisions
P. Moskal, H.-H. Adam, J.T. Balewski, A. Budzanowski, J. Budzinski, D. Grzonka, L. Jarczyk, M. Siemaszko, J. Smyrski, A. Strzalkowski et al.
abstract
We describe a novel technique for comparing total cross sections for the reactions pp --> pp pi(0), pp --> pp eta, and pp --> pp eta' close to threshold. The initial and final state proton-proton interactions are factored out of the total cross section, and the dependence of this reduced cross section on the volume of phase space is discussed. Different models of the proton-proton interaction are compared. We argue that the scattering length of the S-wave eta'-proton interaction is of the order of 0.1 fm.
Energy dependence of the near threshold total cross-section for the p p -> p p eta-prime reaction
P. Moskal, H.-H. Adam, J.T. Balewski, V. Baru, A. Budzanowski, D. Grzonka, J. Haidenbauer, L. Jarczyk, A. Khoukaz, K. Kilian, M. Koehler, P. Kowina, A. Kudryavtsev, N. Lang, J. Smyrski, A. Strzałkowski et al.
abstract
Total cross sections for the pp --> pp eta' reaction have been measured in the excess energy range from Q = 1.53 MeV to Q = 23.64 MeV. The experiment has been performed at the internal installation COSY-11 using a stochastically cooled proton beam of the COoler SYnchrotron COSY and a hydrogen cluster target. The determined energy dependence of the total cross section weakens the hypothesis of the S-wave repulsive interaction between the eta' meson and the proton. New data agree well with predictions based on the phase-space distribution modified by the proton-proton final-state-interaction (FSI) only.
Near threshold eta meson production in proton proton collisions
J. Smyrski, ..., A. Budzanowski, H. Dombrowski, D. Grzonka, P. Kowina, P. Moskal et al.
abstract
The production of eta mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies in the range from 0.5 MeV to 5.4 MeV. The energy dependence of the total cross section is well described by the available phase-space volume weighted by FSI factors for the proton-proton and proton-eta pairs.
Near-threshold eta meson production in proton-proton collisions
J. Smyrski, P. Wustner, JT. Balewski, A. Budzanowski, H. Dombrowski, D. Grzonka, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, P. Kowina, M. Kohler, T. Lister, P. Moskal, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, S. Sewerin, A. Strzalkowski, M. Wolke
abstract
The production of eta masons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies (epsilon) in the range from epsilon = 0.5 MeV to epsilon = 5.4 MeV. The energy dependence of the total cross section is well described by the available phase-space volume weighted by FSI factors for the proton-proton and proton-eta pairs. (C) 2000 Elsevier Science B.V. All rights reserved.
Near threshold hyperon-production at COSY-11 in the reactions pp -> pK(+) Lambda and pp -> pK(+)Sigma(0)
S. Sewerin, JT. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, T. Lister, P. Moskal, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner, W. Eyrich, M. Fritsch, J. Haidenbauer, C. Hanhart, F. Stinzing, C. Wilkin
abstract
At the internal COSY-11 facility the reactions pp --> pK(+)Lambda and pp --> pK(+)Sigma(0) have been measured at excess energies up to 13 MeV. The total cross sections for the Lambda-production have been determined to be a factor of approximate to 28 higher than for the Sigma(0)-production at equivalent excess energies. This observation is in contrast to a cross section ratio of 2-3, obtained at higher excess energies between 300 MeV and 1500 MeV. It is discussed that a strong Sigma(0)p FSI might cause the low cross section for the Sigma(0)-production near threshold due to a Sigma N --> Lambda N conversion.
Near threshold production of eta, eta ' and charged kaon pairs in proton-proton collisions
A. Khoukaz, HH. Adam, JT. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, L. Jarczyk, M. Jochmann, K. Kilian, N. Lang, T. Lister, P. Moskal, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, S. Sewerin, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner, D. Wyrwa
abstract
The near threshold production of eta- and eta'-mesons in proton-proton collisions has been measured at excess energies up to 6.3 MeV and 25.0 MeV using the COSY-11 facility. In this region of excess energy the eta' cross sections are much lower compared to pi(0) and eta production. This observation rather excludes a resonant production of the eta'-meson in the threshold region, whereas such a mechanism dominates the eta production close to threshold. Furthermore, close to threshold data on the elementary K+K- production in the proton-proton interaction have been taken at excess energies up to 56.1 MeV.
Measurement of the transverse polarization of positrons from the decay of polarized muons: A status report
K. Bodek, A. Budzanowski, N. Danneberg, W. Fetscher, C. Hilbes, M. Janousch, L. Jarczyk, E. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, GL. Llacer, M. Markiewicz, X. Morelle, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
A new experiment [1] to measure both transverse components of the positron polarization from the decay of polarized muons starts data taking at PSI in Switzerland. The experiment aims at an accuracy of Delta P-T1 = Delta P-T2 = 3 x 10(-3) and by that at an improvement of the existing limit by nearly one order of magnitude. These results will be sensitive tests for the contribution of exotic couplings to muon decay. In particular, the measurement of P-T1 allows the extraction of the so-called low energy Michel parameter eta, the accuracy of which presently limits a more precise model independent determination of the Fermi coupling constant Gr. The measurement of P-T1 is at present the only possibility to best time reversal invariance in a purely leptonic reaction. The physics motivation is discussed together with a description of the experimental setup and results from test measurements.
Measurement of pd -> He-3 eta in the S-11 resonance
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, S. Igel, J. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, G. Lippert, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BR. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
We have measured the reaction pd --> He-3 eta at a proton beam energy of 980 MeV, which is 88.5 MeV above threshold using the new 'germanium wall' detector system. A missing-mass resolution of the detector system of 2.6% was achieved. The angular distribution of the meson is forward peaked. We found a total cross section of (573 +/- 83 (stat.) +/- 69 (syst.)) nb. The excitation function for the present reaction is described by a Breit Wigner form with parameters from photoproduction. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
Meson production in p + d reactions
W. Klimala, M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
Differential cross sections of the pd --> H-3 pi (+) /He-3 pi (0) reactions were measured simultaneously at three beam momenta: 750 MeV/c, 800 MeV/c and 850 MeV/c. The differential cross section of the pd --> He-3 eta was measured at 1675 MeV/c beam momentum. All measurements cover a wide angular range in the CM system. The experiments were performed at the COSY accelerator in Julich, Germany, by means of high purity Germanium Wall detector together with the magnetic spectrometer BIG KARL. Estimated cross sections were compared with the predictions of simple theoretical models. In case of isospin symmetric pd --> H-3 pi (+) /He-3 pi (0) reactions, the average cross section ratio was estimated.
Proton-proton collisions at production thresholds
P. Moskal, HH. Adam, A. Budzanowski, D. Grzonka, L. Jarczyk, A. Khoukaz, K. Kilian, M. Kohler, P. Kowina, N. Lang, T. Lister, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, M. Sokolowski, A. Strzalkowski, M. Wolke, P. Wustner, W. Zipper
abstract
Recent results obtained by the COSY-11 collaboration concerning the production of eta and eta ' mesons in the pp --> ppMeson reaction are presented. A comparison of the production amplitude for the pi (0), eta and eta ' mesons at the same phase space volume allows to conclude that the protonl-eta ' interaction is in the order of, or smaller than, the proton-pi (0) one. A total cross section determined in a preliminary analysis of the data of elementary kaon and antikaon production via the pp --> pp K K+ (-) reaction measured at excess of energy of Q = 17 MeV is reported.
Heavy meson production at COSY-11
P. Moskal, HH. Adam, JT. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, P. Kowina, M. Kohler, T. Lister, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, S. Sewerin, J. Smyrski, A. Strzalkowski, M. Wolke, P. Wustner
abstract
The COSY-11 collaboration has measured the total cross section for the pp --> pp eta' and pp --> pp eta reactions in the excess energy range from Q = 1.5 MeV to Q = 23.6 MeV and from Q = 0.5 MeV to Q = 5.4 MeV, respectively. Measurements have been performed with the total luminosity of 73 nb(-1) for the pp --> pp eta reaction and 1360 nb(-1) for the pp --> pp eta' one. Recent results are presented and discussed.
Hyperon and charged kaon pair production close to threshold
M. Wolke, HH. Adam, JT. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, P. Kowina, T. Lister, P. Moskal, N. Lang, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, S. Sewerin, M. Siemaszko, J. Smyrski, A. Strzalkowski, P. Wustner, W. Zipper
abstract
Close-to-threshold data on the elementary kaon and antikaon production channels in the proton-proton interaction have been taken using the COSY-11 installation at the cooler synchrotron COSY Julich. The experimental technique applied at the internal COSY-11 facility - designed for meson production studies at small excess energies - is outlined. The threshold excitation functions for the kaon-hyperon production via the reactions pp --> pK(+)Lambda and pp --> pK(+)Sigma(0) are presented. The magnitude of the production amplitudes is compared at equal excess energies and physical implications of the observed Sigma(0) suppression in the threshold region are discussed. In addition, within a Dalitz plot analysis the spin-averaged S-wave scattering parameters could be extracted for the Lambda-p channel. With the possibility of detecting all find state particles the elementary antikaon production in the reaction pp --> ppK(+)K(-) has been investigated. Results on the exclusive total cross section fix the scale of the strangeness dissociation into two kaons.
Near threshold two meson production with the pd -> He-3 pi(+)pi(-) and pd -> (HeK+K-)-He-3 reactions
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, C. Wilkin
abstract
Wear threshold two meson production via the reactions pd --> He-3 pi(+)pi(-) and pd --> He-3 K+K- was measured kinematically complete with the MOMO experiment at COSY. The obtained two pion invariant mass spectra and angular distributions depict a remarkable deviation from phase space. The two kaon data are consistent with phase space topped by a clear signal of the phi meson.
Is time reversal invariance violated in muon decay? A measurement of the transverse positron polarization
K. Bodek, A. Budzanowski, N. Danneberg, W. Fetscher, C. Hilbes, L. Jarczyk, K. Kirch, S. Kistryn, J. Klement, K. Kohler, A. Kozela, J. Lang, GL. Llacer, M. Markiewicz, X. Morelle, T. Schweizer, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, J. Zejma
abstract
In the standard model (SM) of electroweak interactions the positron from the decay of polarized positive muons is mainly longitudinally polarized. However the model also predicts a small transverse polarization component P-T1, which lies in the plane spanned by muon-spin and positron momentum. Interference with additional, scalar couplings would result in substantial values for P-T1 as well as in a non-zero Value of the transverse component PT2 which is perpendicular to the above mentioned plane. A nonzero component P-T2, proportional to the imaginary part of a possible scalar coupling, would be the first observation of time reversal violation in a purely leptonic decay. Measuring P-T1, which is proportional to the real part, amounts to a model independent determination of the Fermi-coupling constant. The mu (PT) experiment [1] at the Paul Scherrer Institute will improve the current experimental limits P-T1 = (16 +/- 22) x 10(-3), P-T2 = (7 +/- 23) x 10(-3) by almost one order of magnitude. First preliminary results of the experiment are given.
Meson production in p+d reactions
M. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, J. Ernst, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, J. Ilieva, L. Jarczyk, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, K. Zwoll
abstract
Pion and sl production on the deuteron are studied at energies in the vicinity of the absolute threshold. The data are expected to be sensitive to high momentum components in the deuteron wavefunction as well as to two step processes.
Pion-pion p-wave dominance in the pd -> He-3 pi(+)pi(-) reaction near threshold
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, C. Wilkin
abstract
The cross section for the pd-->He-3 pi(+)pi(-) reaction has been measured in a kinematically complete experiment at a c.m. excess energy of Q = 70 MeV. The striking energy and angular distributions are reproduced in a simple model calculation when it is assumed that the reaction is dominated by p-wave pi(+)pi(-) pairs. This is in complete contrast to the results of inclusive measurements at somewhat higher beam energies which show a strong s-wave ABC enhancement at low pi pi masses. [S0556-2813(99)51111-4].
Measurement of gamma p -> K-0 Sigma(+) at photon energies up to 1.55 GeV
S. Goers, J. Barth, C. Bennhold, M. Bockhorst, W. Braun, A. Budzanowski, R. Burgwinkel, J. Ernst, KH. Glander, J. Hannappel, N. Jopen, H. Jungst, H. Kalinowsky, U. Kirch, FJ. Klein, F. Klein, E. Klempt, A. Kozela, R. Lawall, L. Lindemann, J. Link, T. Mart, D. Menze, W. Neuerburg, M. Paganetti, E. Paul, R. Plotzke, J. Scholmann, I. Schulday, M. Schumacher, WJ. Schwille, F. Smend, J. Smyrski, HN. Tran, MQ. Tran, H. van Pee, R. Wedemeyer, B. Wiegers, FW. Wieland, J. Wisskirchen
abstract
The reaction gamma p --> K(0)Sigma(+) has been measured with the SAPHIR detector at the electron stretcher ring ELSA, The total cross section rises up to a peak value of 1.1 mu b at a photon energy of 1.4 GeV, The differential cross sections d sigma/d Omega are consistent with being flat throughout the measured energy range. The first measurement of the Sigma(+) polarization in photon induced reactions was obtained. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Comment on "total and differential cross sections of p+p ->pi(+)+d reactions down to 275 keV above threshold" - Drochner et al. reply
M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, M. Hawash, S. Igel, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, G. Lippert, H. Machner, R. Maier, C. Nake, B. Razen, P. von Rossen, K. Scho, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
Comparison of Lambda and Sigma 0 Production near Threshold in Proton-Proton Collisions
S. Sewerin, ..., A. Budzanowski, W. Eyrich, C. Goodman, D. Grzonka, L. Jarczyk, K. Kilian, P. Moskal, J. Smyrski et al.
abstract
Threshold measurements of the associated strangeness production reactions pp->pK1L and
pp-> pK1S0 are presented. The most remarkable feature of the data is that at the same excess
energy the total cross section for the S0 production appears to be about a factor of 2816
29 smaller
than for the L particle. It is concluded that strong S0p final state interactions, and in particular the
SN ! Lp conversion reaction, are the likely cause of the depletion in the S signal. This hypothesis
is in line with other experimental evidence in the literature.
The germanium wall of the GEM detector system
M. Betigeri, E. Bialkowski, H. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernste, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, S. Igel, J. Ilieva, L. Jarczyk, M. Jochmann, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, J. Lieb, G. Lippert, H. Machner, A. Magiera, H. Nann, L. Pentchev, HS. Plendl, D. Protic, B. Razen, P. von Rossen, BJ. Roy, R. Siudak, J. Smyrski, RV. Srikantiah, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
A stack of annular detectors made of high-purity germanium was developed. The detectors are position sensitive with radial structures. The first one ("Quirl") is double-sided position sensitive defining 40 000 pixels, the following three (E1, E2 and E3) have 32 wedges each. The Quirl acts as tracker while the other three act as calorimeter. The stack was successfully operated in meson production reactions close to threshold. (C) 1999 Elsevier Science B.V. All rights reserved.
Measurement of gamma p -> K+ Lambda and gamma p -> K+Sigma(0) at photon energies up to 2 GeV
MQ. Tran, J. Barth, C. Bennhold, M. Bockhorst, W. Braun, A. Budzanowski, G. Burbach, R. Burgwinkel, J. Ernst, KH. Glander, S. Goers, B. Guse, KM. Haas, J. Hannappel, K. Heinloth, K. Honscheid, T. Jahnen, N. Jopen, H. Jungst, H. Kalinowsky, U. Kirch, FJ. Klein, F. Klein, E. Klempt, D. Kostrewa, A. Kozela, R. Lawall, L. Lindemann, J. Link, J. Manns, T. Mart, D. Menze, H. Merkel, R. Merkel, W. Neuerburg, M. Paganetti, E. Paul, R. Plotzke, U. Schenk, J. Scholmann, I. Schulday, M. Schumacher, P. Schutz, WJ. Schwille, F. Smend, J. Smyrski, W. Speth, HN. Tran, H. van Pee, V. Vogl, R. Wedemeyer, F. Wehnes, B. Wiegers, FW. Wieland, J. Wisskirchen, A. Wolf
abstract
Associated strangeness production in the reactions gamma p --> K+ Lambda and gamma p --> K(+)Sigma(0) was measured with the SAPHIR detector at the electron stretcher ring ELSA at Bonn. Data on total and differential cross sections and on hyperon polarizations are presented. The total cross section for Lambda production shows a strong threshold enhancement whereas the Sigma(0) data have a maximum at about E-gamma = 1.45 GeV. Along with the angular decomposition of the differential cross section into polynomials, this suggests resonance production. However, the angular distributions of both hyperon polarizations vary only slightly with the photon energy, Lambda and Sigma(0) polarizations show opposite signs and change sign over the angular range. (C) 1998 Elsevier Science B.V. All rights reserved.
Photoproduction of eta '-mesons with the 4 pi-detector SAPHIR
R. Plotzke, J. Barth, W. Braun, R. Burgwinkel, J. Ernst, KH. Glander, S. Goers, J. Hannappel, N. Joepen, HG. Jungst, H. Kalinowsky, U. Kirch, F. Klein, FJ. Klein, E. Klempt, A. Kozela, R. Lawall, J. Link, D. Menze, W. Neuerburg, M. Ostrick, M. Paganetti, E. Paul, H. van Pee, I. Schulday, WJ. Schwille, J. Smyrski, U. Thoma, L. Tiator, MQ. Tran, F. Wehnes, B. Wiegers, FW. Wieland, J. Wisskirchen
abstract
The gamma p --> p eta' reaction was investigated with the 4 pi magnetic spectrometer SAPHIR at ELSA with tagged photons in the energy range from 0.9 to 2.6 GeV. On the basis of six million hadronic events 250 events with five tracks due to the reaction chain gamma p --> p eta' --> p pi(+) pi(-) eta --> p pi(+) pi(-) pi(+) pi(0) were selected. The strong rise of the cross section at threshold and its steep decrease with gamma-energy indicate dominant resonance production. The linear forward rise of the eta' CMS angular distribution is consistent with a coherent excitation of two resonances S-11 and P-11. Assuming dominance of resonance production, the following masses and widths are determined: S-11(M, Gamma) = (1.897 +/- 0.050(-0.002 )(+0.030), 0.396 +/- 0,155 (+0.035)(-0.045 )) GeV and P-11(M, Gamma) = (1.986 +/- 0.026 (+0.010)(-0.030 ), 0.296 +/- 0.100(-0.010 )(+0.060)) GeV, where the first error is of statistical nature while the second represents the systematic error. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
The p+p ->pi(+)+d reaction close to threshold at COSY
M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, S. Igel, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, G. Lippert, H. Machner, R. Maier, C. Nake, B. Razen, P. von Rossen, BR. Roy, K. Scho, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
Differential and total cross sections of the p + p --> pi(+) + d reaction close to threshold were measured employing a magnetic spectrograph with track: reconstruction, a very thin liquid hydrogen target and an accelerated proton beam with high phase space density.. The data resolve a previous discrepancy between the n + p --> pi(0) + d and the pi(+) + d --> 2p reaction close to threshold indicating that isospin symmetry may be broken in the s-wave part of the cross section. (C) 1998 Elsevier Science B.V.
Meson production studied with the GEM detector
W. Garske, MG. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, K. Grewer, A. Hamacher, S. Igel, I. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, BJ. Lieb, G. Lippert, H. Machner, A. Magiera, R. Maier, H. Nann, E. Pentchev, HS. Plendl, D. Prasuhn, D. Protic, B. Razen, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
Measurements of proton induced meson production on hydrogen and deuterium targets using the GEM-detector at COSY are described. Preliminary estimates of the total cross section are presented. Results of the pp --> d pi(+) and pp --> pp pi(o) cross section are in agreement with previous findings. The total cross section of pd --> He-3 pi(o) is consistent with results from pion absorption but a surprisingly large value was found at a beam momentum of 750 MeV/c. The reaction pd --> He-3 eta was measured at two beam energies and was identified by missing mass technique.
Beam energy calibration with meson production
B. Razen, MG. Betigeri, J. Bojowald, A. Budzanowski, A. Chatterjee, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, A. Hamacher, M. Hawash, S. Igel, I. Ilieva, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, BJ. Lieb, G. Lippert, H. Machner, A. Magiera, R. Maier, H. Nann, HS. Plendl, D. Protic, P. von Rossen, B. Roy, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
The magnetic spectrometer BIG KARL is used to get energy calibration fix-points for the external beam of COSY-Julich. These fixpoints were obtained by measuring the meson-production reaction pp --> d pi(+) close to threshold and at the beam momentum, where the forward pions and the backward deuterons have the same momentum.
Recent results on meson production from SAPHIR
F. Klein, J. Barth, M. Bockhorst, W. Braun, R. Burgwinkel, KH. Glander, S. Goers, J. Hannappel, N. Jopen, U. Kirch, FJ. Klein, D. Menze, W. Neuerburg, E. Paul, WJ. Schwille, MQ. Tran, R. Wedemeyer, F. Wehnes, B. Wiegers, FW. Wieland, J. Wisskirchen, J. Ernst, HG. Jungst, H. Kalinowsky, E. Klempt, J. Link, HV. Pee, R. Plotzke, M. Schumacher, F. Smend, HN. Tran, C. Bennhold, A. Kozela, J. Smyrski
abstract
The SAPHIR detector is a magnetic spectrometer for multiparticle final states attached to the 3.5 GeV electron accelerator ELSA. The experiments focus on the photoproduction of associated strangeness in gamma p --> K(+)Lambda, K(+)Sigma(0) and K(0)Sigma(+) final states and the production of the lightest vector mesons rho, omega and phi. In the K(+)Lambda cross section a steep threshold behaviour is observed which is different in the case of K(+)Sigma(0) which is reflected in the differential cross section. Contrary, Lambda and Sigma polarizations show little variation with energy. A bump in the t-distribution for omega-production for E gamma similar or equal to 1.5 GeV could be an indication for a resonance while the production of phi-mesons appears fully diffractive down to energies below 2 GeV.
K-0-Sigma(+) photoproduction with SAPHIR
C. Bennhold, S. Goers, J. Barth, W. Braun, R. Burgwinkel, J. Ernst, KH. Glander, J. Hannapel, N. Jopen, H. Kalinowsky, U. Kirch, F. Klein, FJ. Klein, E. Klempt, A. Kozela, R. Lawall, ZP. Li, J. Link, T. Mart, D. Menze, W. Neuerburg, M. Paganetti, E. Paul, H. van Pee, R. Plotzke, M. Schumacher, WJ. Schwille, F. Smend, J. Smyrski, HN. Tran, MQ. Tran, F. Wehnes, B. Wiegers, FW. Wieland, J. Wisskirchen
abstract
Preliminary results of the analysis of the reaction gamma + p --> K-0 + Sigma(+) are presented. We show the first measurement of the differential cross section and data for the total cross section, which are much improved with respect to previous measurements. The data are compared with model predictions from different isobar and quark models that give a good description of gamma + p --> K+ + Lambda and gamma + p --> K+ + Sigma(0) data in the same energy range. Results of ChPT describe the data adequately et threshold, while isobar models that include hadronic form factors reproduce the data at intermediate energies.
First results on eta ' photoproduction with SAPHIR
J. Ernst, H. Jungst, H. Kalinowsky, E. Klempt, J. Link, H. van Pee, R. Plotzke, J. Barth, W. Braun, R. Burgwinkel, KH. Glander, S. Goers, J. Hannappel, N. Joepen, U. Kirch, F. Klein, FJ. Klein, R. Lawall, D. Menze, W. Neuerburg, M. Paganetti, E. Paul, WJ. Schwille, MQ. Tran, F. Wehnes, B. Wiegers, FW. Wieland, J. Wisskirchen, M. Schumacher, F. Smend, HN. Tran, A. Kozela, J. Smyrski, C. Bennhold
abstract
Low-energy Lambda-p scattering parameters from the pp -> pK(+)Lambda reaction
JT. Balewski, A. Budzanowski, C. Goodman, D. Grzonka, M. Hofmann, L. Jarczyk, A. Khoukaz, K. Kilian, T. Lister, P. Moskal, W. Oelert, IA. Pellmann, C. Quentmeier, R. Santo, G. Schepers, T. Sefzick, S. Sewerin, J. Smyrski, A. Strzalkowski, C. Thomas, C. Wilkin, M. Wolke, P. Wustner, D. Wyrwa
abstract
Constraints on the spin-averaged Lambda p scattering length and effective range have been obtained from measurements of the pp --> pK(+)Lambda reaction close to the production threshold by comparing model phase-space Dalitz plot occupations with experimental ones. The data fix well the position of the virtual bound state in the Lambda p system. Combining this with information from elastic Lambda p scattering measurements at slightly higher energies, together with the fact that the hyperdeuteron is not bound, leads to a new determination of the low energy Lambda p scattering parameters.
eta ' production in proton-proton scattering close to threshold
P. Moskal, JT. Balewski, A. Budzanowski, H. Dombrowski, C. Goodman, D. Grzonka, J. Haidenbauer, C. Hanhart, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, A. Kozela, T. Lister, UG. Meissner, N. Nikolaev, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, M. Sokolowski, A. Strzalkowski, C. Thomas, M. Wolke, P. Wustner, D. Wyrwa
abstract
The pp --> pp eta'(958) reaction has been measured at the cooler synchrotron COSY at Julich using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies Q = 1.5, 1.7, 2.9, and 4.1 MeV have been evaluated to be sigma = 2.5 +/- 0.5, 2.9 +/- 1.1, 12.7 +/- 3.2, and 25.2 +/- 3.6 nb, respectively. In this region of excess energy the eta'(958) cross sections are much lower compared to those of the pi(0) and eta production.
Proton induced deuteron breakup reaction at 65 MeV: Unspecific configurations
K. Bodek, W. Glockle, J. Golak, L. Jarczyk, S. Kistryn, B. Kozlowska, J. Lang, A. Micherdzinska, O. Naviliat-Cuncic, J. Smyrski, M. Sokolowski, J. Sromicki, A. Strzalkowski, H. Witała, J. Zejma, W. Zipper
abstract
Exclusive near threshold two-pion production with the MOMO experiment at COSY
S. Bavink, F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. vonNeumann-Cosel, D. Rosendaal, PV. Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger
abstract
Near threshold two pion production via the reaction pd --> (HE)-H-3 pi(+)pi(-) was measured kinematically complete with the MOMO experiment at COSY. ii remarkable deviation of thr obtained two pion invariant mass spectra from phase space as well as a predominant back to back and sidewise emission of the two pions was observed.
Proton induced deuteron breakup reaction at 65 MeV: Unspecific configurations
K. Bodek, W. Glockle, J. Golak, L. Jarczyk, S. Kistryn, B. Kozlowska, J. Lang, A. Micherdzinska, O. Naviliat-Cuncic, J. Smyrski, M. Sokolowski, J. Sromicki, A. Strzalkowski, H. Witala, J. Zejma, W. Zipper
abstract
Total cross section of the reaction pp -> pK(+)Lambda close to threshold
JT. Balewski, A. Budzanowski, H. Dombrowski, W. Eyrich, C. Goodman, D. Grzonka, J. Haidenbauer, C. Hanhart, J. Hauffe, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, A. Kozela, A. Lister, A. Metzger, P. Moskal, W. Oelert, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, M. Sokolowski, F. Stinzing, A. Strzalkowski, C. Thomas, S. Wirth, M. Wolke, R. Woodward, P. Wustner, D. Wyrwa
abstract
The energy dependence of the total cross section for the pp --> pK(+) Lambda reaction was measured in the threshold region covering the excess energy range up to 7 MeV. Existing model calculations describe the slope of the measured cross sections well, but are too low by a factor of two to three in rate. The data were used for a precise determination of the beam momentum of the COSY-synchrotron. (C) 1998 Elsevier Science B.V.
pp -> d pi(+) precise angular distributions close to threshold from 0.3 to 5 MeV
B. Razen, M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, K. Grewer, S. Igel, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, G. Lippert, H. Machner, R. Maier, C. Nake, P. von Rossen, K. Scho, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
For the first time the reaction pp-->d pi(+) was measured close to threshold. A magnetic spectrometer (3Q2DQ) which allows ray tracing was applied to detect the recoiling deuterons and reconstruct their momenta. The measured anisotropies are between 0.008 and 0.29, indicating the importance of p-wave amplitudes even close to threshold. The presented data support the validity of isospin and time reversal symmetries.
Threshold measurements at the internal experimental facility COSY-11
J. Balewski, S. Brauksiepe, A. Budzanowski, H. Dombrowski, C. Goodman, D. Grzonka, J. Haidenbauer, C. Hanhart, A. Hardt, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, A. Kozela, T. Lister, R. Maier, P. Moskal, W. Oelert, D. Prasuhn, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, M. Sokolowski, A. Strzalkowski, M. Wolke, P. Wustner
abstract
The experimental setup and detection technique of the COSY-11 installation, an internal experimental facility at the cooler synchrotron and storage ring COSY Julich, are described. The detection system has been designed for meson production studies with full geometrical acceptance close to threshold. Preliminary results of first measurements are presented, emphasis is put on strangeness production in the reactions pp-->ppK(+)K(-) and pp-->pK(+)Lambda.
Polarimetry of N-16(gs) produced in mu(-)-capture on O-16 nuclei
CP. Bee, D. Conti, M. Hadri, S. Kistryn, J. Lang, O. NaviliatCuncic, J. Sromicki, E. Stephan, K. Bodek, J. Smyrski, A. Strzalkowski, J. Zejma, L. Grenacs, R. Abela, P. Boni, F. Foroughi, W. Zipper, A. Proykova
abstract
A polarimetry technique based on stack targets and beta-gamma-coincidences has been applied to the N-16 nuclei produced in the ground state capture of negative muons on O-16 nuclei. The performance of the polarimeter and the first measurements of beta-asymmetry due to the longitudinal nuclear polarization are discussed.
Cross sections and analysing powers A(y) in the breakup reaction H-2((p)over-right-arrow,pp)n at 65 MeV: Star configurations
J. Zejma, M. Allet, K. Bodek, J. Lang, R. Muller, S. Navert, O. NaviliatCuncic, J. Sromicki, E. Stephan, L. Jarczyk, S. Kistryn, J. Smyrski, A. Strzalkowski, W. Glockle, J. Golak, D. Huber, H. Witała, PA. Schmelzbach
abstract
Cross-section and vector-analyzing-power data for three star configurations of the H-2((p) over right arrow,pp)n breakup reaction at E(p)(lab)=65 MeV were measured in a kinematically complete experiment. They are compared to rigorous Faddeev calculations involving five realistic charge-dependent nucleon-nucleon potentials: Argonne v(18), CD Bonn, Nijmegen 93, Nijmegen I, and Nijmegen II. A general satisfactory agreement between theory and experiment has been found. However, there exist also a few minor discrepancies in cross sections in some regions of phase space. The experimental data are compared also to the calculations including the (pi-pi) Tucson-Melbourne three-body force. Their effects are either negligible or increase the disagreement with the experiment.
Exclusive near threshold two-pion production with the MOMO experiment at COSY
S. Bavink, F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, H. Machner, A. Magiera, R. Maschuw, T. Mayer-Kuckuk, G. Mertler, J. Munkel, P. von Neumann-Cosel, D. Rosendaal, P. von Rossen, H. Schnitker, K. Scho, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger
abstract
Near threshold two pion production via the reaction pd --> He-3 pi(+)pi(-) was measured kinematically complete with the MOMO experiment at COSY. A remarkable deviation of the obtained two pion invariant mass spectra from phase space as well as a predominat sidewise and back to back emission of the two mesons was observed.
Lambda-Hyperon production via the pp->pK(+)Lambda reaction 2 MeV above threshold
JT. Balewski, A. Budzanowski, H. Dombrowski, C. Goodman, D. Grzonka, J. Haidenbauer, C. Hanhart, L. Jarczyk, M. Jochmann, A. Khoukaz, K. Kilian, M. Kohler, A. Kozela, T. Lister, R. Maier, P. Moskal, W. Oelert, D. Prasuhn, C. Quentmeier, R. Santo, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, M. Sokolowski, A. Strzalkowski, M. Wolke, P. Wustner
abstract
The pp --> pK(+)Lambda reaction was measured at COSY with a proton beam momentum of 2.345 GeV/c, i.e. with an excess energy of 2 MeV above threshold. The total cross section was determined to be 8.2 +/- 1.8 nb. The present data point close to the production threshold indicates, that existing phenomenological parametrizations of the total kaon production cross section are insufficient.
Meson production in p+p interaction at threshold
JT. Balewski, R. Bilger, A. Budzanowski, H. Clement, KH. Diart, H. Dombrowski, K. Fohl, C. Goodman, D. Grzonka, H. Gutschmidt, K. Heitlinger, L. Jarczyk, M. Jochmann, M. Karnadi, A. Khoukaz, K. Kilian, M. Kohler, A. Kozela, T. Lister, P. Moskal, R. Nellen, W. Oelert, C. Quentmeier, R. Santo, D. Schapler, G. Schepers, U. Seddik, T. Sefzick, J. Smyrski, M. Sokolowski, A. Strzalkowski, M. Wolke, GJ. Wagner, KH. Watzlawik, P. Wustner, K. Zwoll
abstract
First results of the COSY-11 collaboration are presented in this paper. The motivation for the investigation of meson production is discussed. The description of the COSY-11 experimental apparatus, including the method of particle identification and luminosity monitoring will be shown. Preliminary results of first test measurements for the production of (pi(+) pi(-)), eta,eta', and (K+K-) mesons in the p+p interaction will be given. Furthermore,the results of a test for the pp --> pK(+)Lambda reaction is presented.
Two-pion production at MOMO
F. Bellemann, A. Berg, J. Bisplinghoff, G. Bohlscheid, J. Ernst, R. Frascaria, C. Henrich, F. Hinterberger, R. Ibald, R. Jahn, L. Jarczyk, R. Joosten, A. Kozela, U. Kuhn, H. Machner, A. Magiera, R. Maschuw, T. MayerKuckuk, G. Mertler, B. Metsch, J. Munkel, P. vonNeumannCosel, T. vonOepen, HR. Petry, D. Rosendaal, P. vonRossen, K. Scho, F. SChwandt, R. Siebert, J. Smyrski, A. Strzalkowski, R. Tolle, R. Wurzinger, R. Ziegler
abstract
The reaction pd-->He-3 pi(+)pi(-) was measured at 1150 MeV/c proton beam momentum using MOMO instalation at COSY.
Total and differential cross sections of p+p->pi(+)+d reactions down to 275 keV above threshold
M. Drochner, J. Ernst, S. Fortsch, L. Freindl, D. Frekers, W. Garske, M. Hawash, S. Igel, R. Jahn, L. Jarczyk, G. Kemmerling, K. Kilian, S. Kliczewski, W. Klimala, D. Kolev, T. Kutsarova, G. Lippert, H. Machner, R. Maier, C. Nake, B. Razen, P. vonRossen, K. Scho, R. Siudak, J. Smyrski, A. Strzalkowski, R. Tsenov, PA. Zolnierczuk, K. Zwoll
abstract
The p + p --> pi(+) + d reaction is studied at excess energies between 0.275 and 3.86 MeV. Differential and total cross section were measured employing a magnetic spectrometer with nearly 4 pi acceptance in the center of mass system; The measured anisotropies between 0.008 and 0.29 indicate that the p wave is not negligible even so close to threshold. The data are compared to other data offering no evidence for charge symmetry breaking or time reversal violation. The s-wave and p-wave contributions at threshold are deduced.
COSY-11, an internal experimental facility for threshold measurements
S. Brauksiepe, ..., D. Grzonka, K. Kilian, P. Moskal, J. Smyrski, M. Sokolowski, A. Strzałkowski et al.
abstract
The COSY-11 installation is an internal experiment at the cooler synchrotron and storage ring COSY Jülich. It has been designed for full geometrical acceptance close to threshold for meson production studies, especially in the 1 GeV/c2 mass range. The experimental setup makes use of a regular C-type COSY dipole magnet, following a cluster target, to separate reaction products from the beam and to analyze their momenta, thus allowing the observation of charged reaction products at small angles with beam energies close to threshold. Resonances will be identified by missing mass reconstructions from measured four-momenta of two outgoing protons in the predominantly studied pp ? ppX reaction. In addition, charged mesons either produced directly or from decays of X will be detected. The different components of the experimental facility are presented.
Effects of the Tucson-Melbourne three-nucleon force in the proton-deuteron breakup process at E(p)=65 MeV
M. Allet, K. Bodek, J. Golak, W. Glockle, W. Hajdas, D. Huber, L. Jarczyk, H. Kamada, S. Kistryn, J. Lang, R. Muller, O. NaviliatCuncic, J. Smyrski, J. Sromicki, A. Strzalkowski, H. Witała, J. Zejma
abstract
We present the calculated cross sections and vector analyzing powers using the Bonn B nucleon-nucleon potential and the Tucson-Melbourne three-nucleon force (3NF) for six collinearity and quasi-free scattering breakup configurations. These calculations are compared to the results of the recent kinematically complete pd experiments at E(p) = 65 MeV. The Tucson-Melbourne 3NF, adjusted together with the Bonn B potential to reproduce the triton binding energy, leads to small effects both in cross sections and analyzing powers in all six studied configurations.
Proton-induced deuteron breakup at E(p)(lab)=65 MeV in quasi-free scattering configurations
M. Allet, K. Bodek, W. Hajdas, J. Lang, R. Muller, S. Navert, O. NaviliatCuncic, J. Sromicki, J. Zejma, L. Jarczyk, S. Kistryn, J. Smyrski, A. Strzalkowski, H. Witała, W. Glockle, J. Golak, D. Huber, H. Kamada
abstract
The proton-deuteron breakup cross sections and analyzing powers A(y) for three kinematically complete configurations in a quasi-free-scattering geometry have been measured at E(p)(lab) = 65 MeV. The data are compared with predictions of rigorous Faddeev calculations using the Argonne AV14, Bonn-B, Nijmegen-78, and Paris potentials. A satisfactory agreement between theory and experimental data, both for cross sections and analyzing powers, has been found.
Cross sections and vector analyzing powers in the proton induced deuteron breakup reaction at 65 MeV: Star configurations
M. Allet, K. Bodek, W. Glockle, J. Golak, L. Jarczyk, S. Kistryn, J. Lang, R. Muller, S. Navert, O. NaviliatCouncic, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, H. Witała, J. Zejma
abstract
Cross sections and vector analyzing powers in the proton induced deuteron breakup reaction at 65 MeV: Star configurations
M. Allet, K. Bodek, W. Glockle, J. Golak, L. Jarczyk, S. Kistryn, J. Lang, R. Muller, S. Navert, O. NaviliatCouncic, J. Smyrski, J. Sromicki, E. Stephan, A. Strzalkowski, H. Witala, J. Zejma
abstract
Proton-induced deuteron breakup at E(p)(lab)=65 MeV in quasi-free scattering configurations
M. Allet, K. Bodek, W. Hajdas, J. Lang, R. Muller, S. Navert, O. NaviliatCuncic, J. Sromicki, J. Zejma, L. Jarczyk, S. Kistryn, J. Smyrski, A. Strzalkowski, H. Witala, W. Glockle, J. Golak, D. Huber, H. Kamada
abstract
The proton-deuteron breakup cross sections and analyzing powers A(y) for three kinematically complete configurations in a quasi-free-scattering geometry have been measured at E(p)(lab) = 65 MeV. The data are compared with predictions of rigorous Faddeev calculations using the Argonne AV14, Bonn-B, Nijmegen-78, and Paris potentials. A satisfactory agreement between theory and experimental data, both for cross sections and analyzing powers, has been found.
