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.
Study of excited Xi baryons with the PANDA detector
G. Barucca, F. Davi, G. Lancioni, P. Mengucci, L. Montalto, P. P. Natali, N. Paone, D. Rinaldi, L. Scalise, B. Krusche, M. Steinacher, Z. Liu, C. Liu, B. Liu, X. Shen, S. Sun, G. Zhao, J. Zhao, M. Albrecht, W. Alkakhi, S. Bökelmann, S. Coen, F. Feldbauer, M. Fink, J. Frech, V. Freudenreich, M. Fritsch, J. Grochowski, R. Hagdorn, F. H. Heinsius, T. Held, T. Holtmann, I. Keshk, H. Koch, B. Kopf, M. Kümmel, M. Küßner, J. Li, L. Linzen, S. Maldaner, J. Oppotsch, S. Pankonin, M. Pelizä, S. Pflüger, J. Reher, G. Reicherz, C. Schnier, M. Steinke, T. Triffterer, C. Wenzel, U. Wiedner, H. Denizli, N. Er, U. Keskin, S. Yerlikaya, A. Yilmaz, R. Beck, V. Chauhan, C. Hammann, J. Hartmann, B. Ketzer, J. Müllers, 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, P. Lebiedowicz, K. Pysz, W. Schäfer, A. Szczurek, M. Firlej, T. Fiutowski, M. Idzik, J. Moron, K. Swientek, P. Terlecki, G. Kor
abstract
The study of baryon excitation spectra provides insight into the inner structure of baryons. So far, most of the worldwide efforts have been directed towards N* and Delta spectroscopy. Nevertheless, the study of the double and triple strange baryon spectrum provides independent information to the N* and Delta spectra. The future antiproton experiment PANDA will provide direct access to final states containing a XiXi pair, for which production cross sections up to microbarn are expected in p(anti)p reactions. With a luminosity of L=10^31 cm^2 s^-1 in the first phase of the experiment, the expected cross sections correspond to a production rate of ~10^6 events /day . With a nearly 4pi detector acceptance, PANDA will thus be a hyperon factory. In this study, reactions of the type p(anti)p -> Xi+Xi*- as well as p(anti)p -> Xi*+ Xi- with various decay modes are investigated. For the exclusive reconstruction of the signal events, a full decay tree fit is used, resulting in reconstruction efficiencies between 3 and 5%. This allows high statistics data to be collected within a few weeks of data taking.
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.
Odd-even staggering in the yields of intermediate mass fragments from p+Ag collisions at Ep = 480 MeV
U. Singh, B. Kamys , S. Sharma, K. Pysz
abstract
The experimental total production cross-sections of intermediate-mass fragments (isotopes of Li, Be, B, C, N, O, F, Ne, Na, and Mg) were extracted by integration of d2s/dOmegadE data measured at several angles for p+Ag collisions at proton beam energy of 480 MeV. The total cross sections show typical odd?even staggering (OES) when presented as a function of the atomic number Z of ejectiles. The effect is the strongest for products with N = Z and N = Z + 2. Similar behaviour is observed for theoretical cross sections evaluated in the two-step model in which the first stage of the reaction is described by intranuclear cascade INCL++ and the second stage by GEMINI++ model or by two other models, namely ABLA07 and SMM. The OES seems to be even more pronounced for theoretical than for the experimental cross sections.
Technical design report for the (P)over-barANDA Barrel DIRC detector
B. Singh, W. Erni, B. Krusche, M. Steinacher, N. Walford, B. Liu, H. Liu, Z. Liu, X. Shen, C. Wang, J. Zhao, M. Albrecht, T. Erlen, F. Feldbauer, M. Fink, M. Fritsch, J. Haase, FH. Heinsius, T. Held, T. Holtmann, I. Keshk, H. Koch, B. Kopf, M. Kuhlmann, M. Kummel, S. Leiber, M. Mikirtychyants, P. Musiol, A. Mustafa, M. Pelizaus, A. Pitka, J. Pychy, M. Richter, C. Schnier, T. Schroder, C. Sowa, M. Steinke, T. Triffterer, U. Wiedner, M. Ball, R. Beck, C. Hammann, B. Ketzer, M. Kube, P. Mahlberg, M. Rossbach, C. Schmidt, R. Schmitz, U. Thoma, M. Urban, D. Walther, C. Wendel, A. Wilson, A. Bianconi, M. Bragadireanu, D. Pantea, B. Patel, W. Czyzycki, M. Domagala, G. Filo, J. Jaworowski, M. Krawczyk, E. Lisowski, F. Lisowski, M. Michalek, P. Poznanski, J. Plazek, K. Korcyl, A. Kozela, P. Kulessa, P. Lebiedowicz, K. Pysz, et al.
abstract
The (P) over bar ANDA (anti-Proton ANnihiliation at DArmstadt) experiment will be one of the four flagship experiments at the new international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. (P) over bar ANDA will address fundamental questions of hadron physics and quantum chromodynamics using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c and a design luminosity of up to 2 x 10(32) cm(-2) S-1. Excellent particle identification (PID) is crucial to the success of the (P) over bar ANDA physics program. Hadronic PID in the barrel region of the target spectrometer will be performed by a fast and compact Cherenkov counter using the detection of internally reflected Cherenkov light (DIRC) technology. It is designed to cover the polar angle range from 22 degrees to 140 degrees and will provide at least 3 standard deviations (s.d.) pi/K separation up to 3.5 GeV/c, matching the expected upper limit of the final state kaon momentum distribution from simulation. This documents describes the technical design and the expected performance of the (P) over bar ANDA Barrel DIRC detector. The design is based on the successful BaBar DIRC with several key improvements. The performance and system cost were optimized in detailed detector simulations and validated with full system prototypes using particle beams at GSI and CERN. The final design meets or exceeds the PID goal of clean pi/K separation with at least 3 s.d. over the entire phase space of charged kaons in the Barrel DIRC.
Search for C violation in the decay eta -> pi(0)e(+)e(-) with WASA-at-COSY
R. Adlarson, WAC. Collaboration, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, A. Bondar, M. Buescher, H. Calen, I. Ciepal, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, R. Fedorets, K. Foehl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Huesken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, A. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, R. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, R. Marciniewski, B. Marianski, HP. Morsch, R. Moskal, H. Ohm, W. Parol, EP. Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, et al.
abstract
We report on the search for the rare decay eta -> pi(0)e(+)e(-) which is of interest to study C violation in the electromagnetic interaction which would indicate contributions from physics beyond the Standard Model, since the allowed decay via a two-photon intermediate state is strongly suppressed. The experiment has been performed using the WASA-at-COSY installation, located at the COSY accelerator of the Forschungszentrum Julich, Germany. In total 3 x 10(7) events of the reaction pd -> He-3 eta have been recorded at an excess energy of Q = 59.8MeV. Based on this data set the C parity violating decay eta -> pi(0)gamma* -> pi(0)e(+)e(-) via a single-photon intermediate state has been searched for, resulting in new upper limits of Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> pi(+) pi(-) pi(0)) < 3.28 x 10(-5) and Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> all)< 7.5 x 10(-6) (CL=90%), respectively. (c) 2018 The Author. Published by Elsevier B.V.
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.
Total and differential cross sections of eta-production in proton-deuteron fusion for excess energies between Q(eta)=13 MeV and Q(eta)=81 MeV
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. Erveno, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, A. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, 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. Piskunovu, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
New data on both total and differential cross sections of the production of eta mesons in proton-deuteron fusion to He-3 eta in the excess energy region 13.6 MeV <= Q(eta) <= 80.9 MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between p(p) = 1.60 GeV/c and p(p) = 1.74 GeV/c. While significant structure of the total cross section is observed in the energy region 20 MeV less than or similar to Q(eta) less than or similar to 60 MeV, a previously reported sharp variation around Q(eta) approximate to 50 MeV cannot be confirmed. Angular distributions show the typical forward- peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval. (c) 2018 The Author. Published by Elsevier B.V.
Importance of d-wave contributions in the charge symmetry breaking reaction dd -> He-4 pi0
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, CO. Gullstrom, C. Hanhart, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, 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, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
This letter reports a first quantitative analysis of the contribution of higher partial waves in the charge symmetry breaking reaction dd -> He-4 pi(0) using the WASA-at-COSY detector setup at an excess energy of Q = 60 MeV. The determined differential cross section can be parametrized as d sigma/d Omega = a + b cos(2) theta*, where theta* is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a = (1.55 +/- 0.46(stat)(-0.8)(+0.32)(syst)) pb/sr and b = (13.1 +/- 2.1(stat)(-2.7)(+1.0)(syst)) pb/sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the A isobar to the dd -> He-4 pi(0) reaction and is, therefore, crucial for a quantitative understanding of quark mass effects in nuclear production reactions. (C) 2018 The Author(s). Published by Elsevier B.V.
Spin Dependence of eta Meson Production in Proton-Proton Collisions Close to Threshold
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, SD. Bass, 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, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, 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, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction (p) over right arrowp -> pp eta has been measured close to threshold to explore the analyzing power A(y). The angular distribution of A(y) is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q = 15 MeV, signaling s-wave production with no evidence for higher partial waves. At Q = 72 MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)(2) and Ss*Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the eta meson.
Non-equilibrium processes in p plus Ag collisions at GeV energies
M. Fidelus, D. Filges, F. Goldenbaum, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, SK. Sharma, R. Siudak, M. Wojciechowski
abstract
The double differential spectra d(2)sigma/d Omega dE of p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11,B-12 were measured at seven scattering angles, 15.6 degrees, 20 degrees, 35 degrees, 50 degrees, 65 degrees, 80 degrees, and 100 degrees, in the laboratory system for proton induced reactions on a silver target. Measurements were done for three proton energies: 1.2, 1.9, and 2.5 GeV. The experimental data were compared to calculations performed by means of two-step theoretical microscopic models. The first step of the reaction was described by the intranuclear cascade model INCL4.6 and the second one by four different models (ABLA07, GEM2, GEMINI++, and SMM) using their standard parameter settings. Systematic deviations of the data from predictions of the models were observed. The deviations were especially large for the forward scattering angles and for the kinetic energy of emitted particles in the range from about 50 to 150 MeV. This suggests that some important non-equilibrium mechanism is lacking in the present day microscopic models of proton-nucleus collisions in the studied beam energy range.
Isoscalar single-pion production in the region of Roper and d*(2380) resonances
P. Adlarsona, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, 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, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, 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, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Exclusive measurements of the quasi-free pn -> pp pi(-) and pp -> pp pi(0) reactions have been performed by means of pd collisions at T-p= 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region T-p= 0.95-1.3 GeV (root s = 2.3-2.46 GeV), which includes the regions of triangle(1232), N*(1440) and d*(2380) resonance excitations. From these measurements the isoscalar single-pion production has been extracted, for which data existed so far only below T-p = 1 GeV. We observe a substantial increase of this cross section around 1 GeV, which can be related to the Roper resonance N*(1440), the strength of which shows up isolated from the triangle resonance in the isoscalar (N pi)(I=0) invariant-mass spectrum. No evidence for a decay of the dibaryon resonance d*(2380) into the isoscalar (NN pi)(I=0) channel is found. An upper limit of 180 mu b (90% CL.) corresponding to a branching ratio of 9% has been deduced. (c) 2017 The Author(s). Published by Elsevier B.V.
Measurement of the omega -> pi(+)pi(-)pi(0) Dalitz plot distribution The WASA-at-COSY Collaboration
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, 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, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. RudyC, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Using the production reactions pd -> He-3 omega and pp -> pp omega, the Dalitz plot distribution for the omega -> pi(+)pi(-)pi(0)decay is studied with the WASA detector at COSY, based on a combined data sample of (4.408 +/- 0.042) x 10(4) events. The Dalitz plot density is parametrised by a product of the P-wave phase space and a polynomial expansion in the normalised polar Dalitz plot variables Z and phi. For the first time, a deviation from pure P-wave phase space is observed with a significance of 4.1 sigma. The deviation is parametrised by a linear term 1+2 alpha Z, with alpha determined to be +0.147 +/- 0.036, consistent with the expectations of rho-meson-type final-state interactions of the P-wave pion pairs. (C) 2017 The Author. Published by Elsevier B.V.
Search for eta-mesic He-4 in the dd -> (3)Hen pi(0) and dd -> (3)Hep pi(-) reactions with the WASA-at-COSY facility
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, 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, E. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, NG. Kelkar, G. Kemmerling, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magierae, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
The search for He-4-eta bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd -> (3)Hen pi(0) and dd -> (3)Hep pi(-) processes. The deuteron beam momentum was varied continuously between 2.127 GeV/c and 2.422 GeV/c, corresponding to the excess energy for the dd -> He-4 eta reaction ranging from Q = 70 MeV to Q = 30 MeV. The luminosity was determined based on the dd -> (3)Hen reaction and the quasi-free proton proton scattering via dd -> ppn(spectator)n(spectator) reactions. The excitation functions, determined independently for the measured reactions, do not reveal a structure which could be interpreted as a narrow mesic nucleus. Therefore, the upper limits of the total cross sections for the bound state production and decay in dd -> (4He-eta)(bound) -> (3)Hen pi(0) and dd -> (He-4-eta)(bound) -> (3)Hep pi(-) processes were determined taking into account the isospin relation between the both of the considered channels. The results of the analysis depend on the assumptions of the N* (1535) momentum distribution in the anticipated mesic-He-4. Assuming, as in the previous works, that this is identical with the distribution of nucleons bound with 20 MeV in He-4, we determined that (for the mesic bound state width in the range from 5 MeV to 50 MeV) the upper limits at 90% confidence level are about 3 nb and about 6 nb for n pi(0) and p pi(-) channels, respectively. However, based on the recent theoretical findings of the N*(1535) momentum distribution in the N*-He-3 nucleus bound by 3.6 MeV, we find that the WASA-at-COSY detector acceptance decreases and hence the corresponding upper limits are 5 nb and 10 nb for n pi(0) and p pi(-) channels respectively. (C) 2017 Elsevier B.V. All rights reserved.
Feasibility study for the measurement of piN transition distribution amplitudes at PANDA in vec{p}p->J/psi pi0
B. Singh, W. Erni, B. Krusche, M. Steinacher, N. Walford, H. Liu, Z. Liu, B. Liu, X. Shen, C. Wang, J. Zhao, M. Albrecht, T. Erlen, M. Fink, FH. Heinsius, T. Held, T. Holtmann, S. Jasper, I. Keshk, H. Koch, B. Kopf, M. Kuhlmann, M. Kummel, S. Leiber, M. Mikirtychyants, P. Musiol, A. Mustafa, M. Pelizaeus, J. Pychy, M. Richter, C. Schnier, T. Schroder, C. Sowa, M. Steinke, T. Triffterer, U. Wiedner, M. Ball, R. Beck, C. Hammann, B. Ketzer, M. Kube, P. Mahlberg, M. Rossbach, C. Schmidt, R. Schmitz, U. Thoma, M. Urban, D. Walther, C. Wendel, A. Wilson, A. Bianconi, M. Bragadireanu, M. Caprini, D. Pantea, B. Patel, W. Czyzycki, M. Domagala, G. Filo, J. Jaworowski, M. Krawczyk, E. Lisowski, F. Lisowski, M. Michalek, P. Poznanski, J. Plazek, K. Korcyl, A. Kozela, P. Kulessa, P. Lebiedowicz, K. Pysz, W. Schaefer, et al.
abstract
The exclusive charmonium production process in p?p annihilation with an associated pi0 meson vec{p}p ->J=psi pi 0 is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J=psi -> e+e- decay channel with the AntiProton ANnihilation at DArmstadt (PANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the vec{p}p -> pi+pi-pi0 and vec{p} -> J=psi pi0 pi0 reactions are performed with PANDA ROOT , the simulation and analysis software framework of the PANDA experiment. It is shown that the measurement can be done at P?ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.
Measurements of branching ratios for eta decays into charged particles
P. AdlarsoN, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, et al.
abstract
The WASA-at-COSY experiment has collected 3 x 10(7) events with eta mesons produced via the reaction pd -> He-3 eta at T = 1.0 GeV. Using this data set, we evaluate the branching ratios of the decays eta -> pi(+)pi(-)gamma, eta -> e(+)e(-)gamma, eta -> pi(+)pi(-)e(+)e(-), and eta -> e(+)e(-)e(+)e(-). The branching ratios are normalized to the eta -> pi(+)pi(-) pi(0) decay. In addition an upper limit on a CP-violating asymmetry in eta -> pi(+)pi(-)e(+)e(-) is extracted.
Search for an isospin I=3 dibaryon
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, 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, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, O. Khreptak, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhnl, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, et al.
abstract
Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance d*(2380) with I(J(P)) = 3(0(+)) there should also exist a dibaryon resonance with mirrored quantum numbers I(J(P)) = 3(0(+)). We report here on a search for such a NN-decoupled state in data on the pp -> pp pi(+) pi(+) pi(-) pi(-) reaction. Since no clear-cut evidence has been found, we give upper limits for the production cross section of such a resonance in the mass range 2280-2500 MeV. (C) 2016 The Author(s). Published by Elsevier B.V.
Study of doubly strange systems using stored antiprotons
B. Singh, W. Erni, B. Krusche, M. Steinacher, N. Walford, B. Liu, H. Liu, Z. Liu, X. Shen, C. Wang, J. Zhao, M. Albrecht, T. Erlen, M. Fink, F. Heinsius, T. Held, T. Holtmann, S. Jasper, I. Keshk, H. Koch, B. Kopf, M. Kuhlmann, M. Kummel, S. Leiber, M. Mikirtychyants, P. Musiol, A. Mustafa, M. Pelizaus, J. Pychy, M. Richter, C. Schnier, T. Schroder, C. Sowa, M. Steinke, T. Triffterer, U. Wiedner, M. Ball, R. Beck, C. Hammann, B. Ketzer, M. Kube, P. Mahlberg, M. Rossbach, C. Schmidt, R. Schmitz, U. Thoma, M. Urban, D. Walther, C. Wendel, A. Wilson, A. Bianconi, M. Bragadireanu, M. Caprini, D. Pantea, B. Patel, W. Czyzycki, M. Domagala, G. Filo, J. Jaworowski, M. Krawczyk, E. Lisowski, F. Lisowski, M. Michalek, P. Poznanski, J. Plazek, K. Korcyl, A. Kozela, P. Kulessa, P. Lebiedowicz, K. Pysz, W. Schafer, et al.
abstract
Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions. (C) 2016 Elsevier B.V. All rights reserved.
Measurement of the (n)over-right-arrowp -> d pi(0) pi(0) reaction with polarized beam in the region of the d(*)(2380) resonance
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Caleen, I. Ciepa, H. Clement, E. Czerwinski, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Foohl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, CO. Gullstrom, L. Heijkenskjold, V. Hejny, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, G. Khatri, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, HP. Morsch, P. Moskal, H. Ohm, EP. del Rio, NM. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schatti-Ozerianska, T. Sefzick, V. Serdyuk, et al.
abstract
We report on a high-statistics measurement of the most basic double-pionic fusion reaction over the energy region of the d (*)(2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d(*) resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.
Measurement of the np -> np pi(0)pi(0) reaction in search for the recently observed d* (2380) resonance
P. Adlarsona, W. Augustyniak, W. Bardan, M. Bashkanov, FS. Bergmann, M. Berlowski, H. Bhatt, A. Bondar, M. Buscher, H. Calen, I. Ciepal, H. Clement, D. Coderre, E. Czerwinski, K. Demmich, E. Doroshkevich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Fohl, K. Fransson, F. Goldenbaum, P. Goslawski, A. Goswami, K. Grigoryev, CO. Gullstrom, F. Hauenstein, L. Heijkenskjold, V. Hejny, B. Hoistad, N. Husken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, FA. Khan, A. Khoukaz, DA. Kirillov, S. Kistryn, H. Kleines, B. Klos, W. Krzemien, P. Kulessa, A. Kupsc, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Marianski, M. Mikirtychiants, HP. Morsch, P. Moskal, H. Ohm, I. Ozerianska, EP. del Rio, NM. Piskunov, P. Podkopal, D. Prasuhn, A. Pricking, D. Pszczel, K. Pysz, et al.
abstract
Exclusive measurements of the quasi-free np --> np pi(0)pi(0) reaction have been performed by means of dp collisions at T-d = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region root s = (2.35-2.46) GeV, which includes the region of the ABC effect and its associated d* (2380) resonance. Adding the d* resonance amplitude to that for the conventional processes leads to a reasonable description of the data. The observed resonance effect in the total cross section is in agreement with the predictions of Faldt and Wilkin as well with those of Albadajedo and Oset. The ABC effect, i.e. the low-mass enhancement in the pi(0)pi(0)-invariant mass spectrum, is found to be very modest - if present at all, which might pose a problem to some of its interpretations. (C) 2015 The Authors. Published by Elsevier B.V.
Sequential and simultaneous emission of particles from p plus Al collisions at GeV energies
M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, A. Jany, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, SK. Sharma, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11 produced in collisions of 1.2, 1.9, and 2.5 GeV protons with an Al target. It was found that the cross sections are almost independent of the beam energy. The spectra and angular distributions indicate a presence of two contributions: a quasi-isotropic, low-energy one which is attributed to the emission of particles from excited remnants of the intranuclear cascade, and an anisotropic part which is interpreted to originate from the first stage of the reaction. The experimental data are compared with an intranuclear cascade model coupled to evaporation, and to statistical multifragmentation models using their standard parameter settings. It was found that all applied models produce very similar results describing spectra of the intermediate mass fragments. All models also reproduce well the low-energy part of the spectra of light charged particles (below approximate to 30 MeV). The description of the higher energy part (50-150 MeV) of the light charged particles spectra is poorer, deteriorating with decreasing scattering angle and decreasing mass of the particles.
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.
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.
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.
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.
Comparison of nonequilibrium processes in p plus Ni and p plus Au collisions at GeV energies
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t, He-3,He-4,He-6, Li-6,Li-7,Li-8, Be-7,Be-9,Be-10, B-10,B-11, and C produced in collisions of 1.2, 1.9, and 2.5 GeV protons with a Ni target. The shape of the spectra and angular distributions almost does not change whereas the absolute value of the cross sections increases by a factor similar to 1.7 for all ejectiles in this beam energy range. It was found that energy and angular dependencies of the cross sections cannot be reproduced by microscopic models of intranuclear cascade including coalescence of nucleons coupled to statistical model for evaporation of particles from excited, equilibrated residual nuclei. The inclusion of nonequilibrium processes, described by a phenomenological model of the emission from fast and hot moving sources, resulting from break up of the target nucleus, leads to very good reproduction of data. Cross sections of these processes are quite large, exhausting approximately half of the total production cross sections. Due to good reproduction of energy and angular dependencies of d(2)sigma/d Omega dE it was possible to determine total production cross sections for all studied ejectiles. Results obtained in this work point to the analogous reaction mechanism for proton induced reactions on Ni target as that observed previously for Au target in the same beam energy range.
Variation of nonequilibrium processes in the p plus Ni system with beam energy
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE were measured for p,d,t,(3,4)He, (6,7)Li, (7,9)Be, and (10,11)B produced in collisions of 0.175 GeV protons with a Ni target. The analysis of measured differential cross sections allowed the extraction of total production cross sections for the ejectiles listed above. The shape of the spectra and angular distributions indicates the presence of other nonequilibrium processes besides the emission of nucleons from the intranuclear cascade and the evaporation of various particles from remnants of intranuclear cascade. These nonequilibrium processes consist of the coalescence of nucleons into light-charged particles during the intranuclear cascade, of the fireball emission, which contributes to the cross sections of protons and deuterons, and of the breakup of the target nucleus, which leads to the emission of intermediate mass fragments. All such processes were found earlier at beam energies 1.2, 1.9, and 2.5 GeV for Ni and Au targets; however, significant differences in the properties of these processes at high and low beam energy are observed in the present study.
Competition of coalescence and "fireball" processes in nonequilibrium emission of light charged particles from p+Au collisions
A. Budzanowski, M. Fidelus, D. Filges, F. Goldenbaum, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski
abstract
The energy and angular dependence of the double differential cross sections d(2)sigma/d Omega dE were measured for p, d, t,He-3,He-4,He-6, Li-6,Li-7,Li-8,Li-9, Be-7,Be-9,Be-10, and B-10,B-11,B-12 isotopes produced in reactions of 1.2- and 1.9-GeV protons on a Au target. The beam energy dependence of the data, supplemented by the cross sections from a previous experiment at 2.5 GeV, is very smooth. The shape of the spectra and angular distributions do not change significantly in the beam energy range from 1.2 to 2.5 GeV. However, the absolute value of the cross sections increases for all ejectiles. The intermediate mass fragment spectra and their angular distributions are very well reproduced by a phenomenological model of two emitting, moving sources, with parameters smoothly varying with energy. The double differential cross sections for light charged particles were analyzed in the framework of the microscopic model calculations of intranuclear cascade, including the coalescence of nucleons and a statistical model for evaporation of particles from excited residual nuclei. However, the energy and angular dependencies of the data agree with neither predictions of the microscopic intranuclear cascade calculations for protons nor the coalescence calculations for other light charged particles. A very good description of the data is achieved by the phenomenological inclusion of the emission of light charged particles from a "fireball" (i.e., a fast and hot moving source). It was found that the nonequilibrium processes are very important for the production of light charged particles. They exhaust 40%-80% of the total cross section-depending on the emitted particles. Coalescence and fireball emission yield comparable contributions to the cross sections with the exception of the He-3 data where coalescence clearly dominates. For all light charged particles, the ratio of nonequilibrium processes to processes proceeding through a phase of statistical equilibrium does not change significantly between the beam energies of 1.2 and 2.5 GeV.
Non-equilibrium emission of complex fragments from p plus Au collisions at 2.5 GeV proton beam energy
A. Bubak, A. Budzanowski, D. Filges, F. Goldenbaum, A. Heczko, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, E. Kozik, P. Kulessa, H. Machner, A. Magiera, W. Migdal, N. Paul, B. Piskor-Ignatowicz, M. Puchala, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski, P. Wustner
abstract
The energy and angular dependence of double differential cross sections d(2)sigma/d Omega dE was measured for reactions induced by 2.5 GeV protons on Au target with isotopic identification of light products (H, He, Li, Be, and B) and with elemental identification of heavier intermediate mass fragments (C, N, O, F, Ne, Na, Mg, and Al). It was found that two different reaction mechanisms give comparable contributions to the cross sections. The intranuclear cascade of nucleon-nucleon collisions followed by evaporation from an equilibrated residuum describes the low energy part of the energy distributions whereas another reaction mechanism is responsible for the high energy part of the spectra of composite particles. A phenomenological model description of the differential cross sections by isotropic emission from two moving sources led to a very good description of all measured data. Values of the extracted parameters of the emitting sources are compatible with the hypothesis claiming that high energy particles emerge from preequilibrium processes consisting in a breakup of the target into three groups of nucleons; small, fast, and hot fireball of similar to 8 nucleons, and two larger, excited prefragments, which emit light charged particles and intermediate mass fragments. The smaller of them contains similar to 20 nucleons and moves with a velocity larger than the CM velocity of the proton projectile and the target. The heavier prefragment behaves similarly as the heavy residuum of the intranuclear cascade of nucleon-nucleon collisions.
Light charged particle and intermediate mass fragment cross-sections in GeV proton-induced reactions
V. Bollini, A. Bubak, A. Budzanowski, J. Cugnon, D. Filges, F. Goldenbaum, A. Heczko, H. Hodde, L. Jarczyk, B. Kamys, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, P. Kulessa, H. Machner, A. Magiera, W. Migdal, K. Nunighoff, N. Paul, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, R. Siudak, M. Wojciechowski, E. Kozik
abstract
As an international collaboration PISA (Proton Induced SpAllation) has initiated measurements of total and double differential cross-sections for products of spallation reactions at the proton accelerator COSY in Julich (Germany) in order to study secondary particle production created in structural, window, and target materials by proton beams up to 2.5 GeV incident kinetic energy. In the framework of Spallation Neutron Sources and accelerator-driven systems, residual nuclei (H, He up to intermediate mass fragrments) production cross-sections are of great importance for estimation of damage in target and structural materials. Reliable and comprehensive experimental data, especially for p-energies beyond I GeV will serve as benchmarks for code development and validation. Data taken by Bragg curve spectroscopy and silicon detector telescopes for the reaction 1.9 GeV p + Ni(Au) will be discussed and kinetic energy spectra of light ions and intermediate mass fragments will be presented. (c) 2006 Elsevier B.V. All rights reserved.
PISA - an experiment for fragment spectroscopy at the Internal Beam of COSY: application of an Axial Ionization Chamber
R. Barna, V. Bollini, A. Bubak, A. Budzanowski, D. De Pasquale, D. Filges, SV. Fortsch, F. Goldenbaum, A. Heczko, H. Hodde, A. Italiano, L. Jarczyk, B. Kamys, J. Kisiel, M. Kistryn, S. Kistryn, S. Kliczewski, A. Kowalczyk, P. Kulessa, H. Machner, A. Magiera, J. Majewski, W. Migdal, H. Ohm, N. Paul, B. Piskor-Ignatowicz, K. Pysz, Z. Rudy, H. Schaal, R. Siudak, E. Stephan, GF. Steyn, R. Sworst, T. Thovhogi, M. Wojciechowski, W. Zipper
abstract
The Proton-Induced SpAllation (PISA) experiment performed at the internal beam facility of the COSY storage ring in Julich, Germany, which is aimed at the precise measurement of double differential cross-sections over a broad range of energies and angles for spallation reactions induced by protons of 200-2500 MeV energy in various targets, is presented. In this paper the emphasis is put on the design, principles of operation and performance of a Bragg Curve Detector (BCD) optimized for internal beam experiments at storage rings. Very clean and distinct product identification (with Z up to similar to 14) from reactions, in which a Ni target was bombarded with a 1.9 GeV circulating proton beam, is obtained. The individual elements are resolved for emission energies higher than 0.5 MeV/nucleon. Moreover, due to the detector readout achieved by coupling a specially designed current sensitive preamplifier directly to a sampling ADC, the shape analysis of the signals from the BCD allows the isotope identification of light particles with A up to similar to 11. It is also found that the BCD can be used efficiently as a thin DeltaE detector for the telescope consisting of the BCD and a series of silicon detectors. (C) 2003 Elsevier B.V. All rights reserved.
