Comparison of readout systems for high-rate silicon photomultiplier applications
M. L. Wong, M. Kołodziej, K. Briggl, R. Hetzel, G. Korcyl, R. Lalik, A. Malige, A. Magiera, G. Ostrzołek, K. Rusiecka, A. Stahl, V. Urbanevych, M. Wiebusch, A. Wrońska
abstract
Recent years have shown an increased use of silicon photomultipliers (SiPM) in experimentsas they are of reasonable cost, have relatively low power consumption and are easily available in avariety of form factors allowing for a large number of readout channels. At the same time, experimentsare generating data at increasingly high rates requiring the use of more efficient readout systems. Inthis work, the dead time, efficiency, dynamic range, coincidence time resolution and energy resolutionof five different readout systems at various stages of maturity are evaluated to determine the bestsystem for acquiring data from a detector in a high rate experiment. Additional functionalities ofthe systems are also discussed.
Real-Time data processing pipeline for trigger readout board-based data acquisition systems
A. Malige, G. Korcyl, M. Firlej, T. Fiutowski, M. Idzik, B. Korzeniak, R. Lalik, A. Misiak, A. Molenda, J. Moroń, N. Rathod, P. Salabura, K. Świentek, P. Wintz
abstract
Large-scale physics experiments running at high interaction rates place a high demand on the data acquisition system (DAQ) responsible for transporting the data from the detector to the storage. The antiProton ANihilation at DArmstadt (PANDA) at the facility for anti-proton and ion research (FAIR) is one such experiment of the future that will not use fixed hardware triggers; instead, the event selection is based on real-time feature extraction, filtering, and high-level correlations. A firmware framework for such real-time data processing has been developed and tested with hardware setup for a PANDA Forward Tracker (FT) prototype. The solution is applicable for other detector subsystems based on the so-called Trigger Readout Board (TRB) data read-out system.
A systematic study of LYSO:Ce, LuAG:Ce and GAGG:Ce scintillating fibers properties
K. Rusiecka, R. Hetzel, J. Kasper, M. Kazemi Kozani, N. Kohlhase, M. Kołodziej R. Lalik, A. Magiera, W. Migdał, M. Rafecas, A. Stahl, V. Urbanevyvh, M. L. Wong, A. Wrońska
abstract
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.
Identical pion intensity interferometry in central Au plus Au collisions at 1.23A GeV HADES Collaboration
J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, R. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, T. Matulewicz, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, S. Morozov, et al.
abstract
We investigate identical pion HBT intensity interferometry in central Au +Au collisions at 1.23A GeV. High-statistics pi(-)pi(-) and pi(+)pi(+) data are measured with HADES at SIS18/GSI. The radius parameters, derived from the correlation function depending on relative momenta in the longitudinally comoving system and parametrized as three-dimensional Gaussian distribution, are studied as function of transverse momentum. A substantial charge-sign difference of the source radii is found, particularly pronounced at low transverse momentum. The extracted source parameters agree well with a smooth extrapolation of the center-of-mass energy dependence established at higher energies, extending the corresponding excitation functions down towards a very low energy. (C) 2019 The Author(s). Published by Elsevier B.V.
Strong Absorption of Hadrons with Hidden and Open Strangeness in Nuclear Matter
J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, S. Chernenko, L. Chlad, P. Chudoba, I. Ciepal, C. Deveaux, D. Dittert, J. Dreyer, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, F. Kornas, R. Kotte, J. Kubos, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, S. Linev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Malige, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, et al.
abstract
We present the first observation of K- and phi absorption within nuclear matter by means of pi(-)-induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K-/K+)(W)/(K-/K+)(C) is found to be 0.319 +/- 0.009(stat)(-0.012)(+0.014)(syst) indicating a larger absorption of K- in heavier targets as compared to lighter ones. The measured phi/K- ratios in pi(-) + C and pi(-) + W reactions within the HADES acceptance are found to be equal to 0.55 +/- 0.04(stat)(-0.07)(+0.06) (syst) and to 0.63 +/- 0.06(stat)(-0.11)(+0.11)(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the phi meson in nuclear medium is strongly coupled to the K- dynamics. The large difference in the. production off C and W nuclei is discussed in terms of a strong phi N in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.
Sub-threshold production of K-s(0) mesons and Lambda hyperons in Au plus Au collisions at root s(NN)=2.4 GeV
J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, R. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, R. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kamakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, S. Morozov, et al.
abstract
We present first data on sub-threshold production of K-s(0) mesons and Lambda hyperons in Au+Au collisions at root s(NN) = 2.4 GeV. We observe an universal < A(part)> scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their < A(part)> scaling, and the shapes of the rapidity and the p(t) spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of them can simultaneously describe these observables with reasonable chi(2) values. (C) 2019 The Authors. Published by Elsevier B.V.
Collective flow and correlations measurements with HADES in Au plus Au collisions at 1.23 AGeV
B. Kardan, J. Adamczewski-Musch, O. Arnold, B. Arnoldi-Meadows, A. Belounnas, A. Belyaev, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, L. Chlad, P. Chudoba, I. Ciepal, C. Deveaux, D. Dittert, J. Dreyer, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, A. Gillitzer, O. Golosov, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, V. Ivanov, A. Ivashkin, B. Kampfer, M. Kajetanowicz, KH. Kampert, B. Kardan, V. Khomyakov, I. Koenig, W. Koenig, G. Korcyl, G. Kornakov, F. Kornas, R. Kotte, A. Kozela, J. Kubos, A. Kugler, T. Kunz, P. Kurilkin, V. Kushpil, V. Ladygin, R. Lalik, A. Lebedev, S. Linev, L. Lopes, M. Lorenz, G. Lykasov, T. Mahmoud, A. Malakhov, J. Markert, S. Maurus, et al.
abstract
The HADES experiment provides a large acceptance combined with a high mass resolution and therefore makes it possible to study dielectron and hadron production in heavy-ion collisions with unprecedented precision. With the high statistics of seven billion Au+Au collisions at 1.23 AGeV recorded in 2012 the investigation of collective effects and particle correlations is possible with unprecedented accuracy. We present multi-differential data on directed (v(1)) and elliptic (v(2)) flow, and the first measurement of triangular flow (v(3)), of protons and deuterons.
Multi-differential pattern of low-mass e(+)e(-) excess from root S-NN=2.4 GeV Au+Au collisions with HADES
S. Harabasz, J. Adamczewski-Musch, O. Arnold, B. Arnoldi-Meadows, A. Belounnas, A. Belyaev, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, L. Chlad, P. Chudoba, I. Ciepal, C. Deveaux, D. Dittert, J. Dreyer, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, A. Gillitzer, O. Golosov, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, V. Ivanov, A. Ivashkin, B. Kampfer, M. Kajetanowicz, KH. Kampert, B. Kardan, V. Khomyakov, I. Koenig, W. Koenig, G. Korcyl, G. Kornakov, F. Kornas, R. Kotte, A. Kozela, J. Kubos, A. Kugler, T. Kunz, P. Kurilkin, V. Kushpil, V. Ladygin, R. Lalik, A. Lebedev, S. Linev, L. Lopes, M. Lorenz, G. Lykasov, T. Mahmoud, A. Malakhov, J. Markert, S. Maurus, et al.
abstract
The matter formed in central heavy-ion collisions at a few GeV per nucleon is commonly understood as resonance matter, a gas of nucleons and excited baryon states with a substantial contribution from mesonic, mostly pionic excitations. Yet, in the initial phase of the reaction the system is compressed to beyond nuclear ground state density and hence substantial modifications of the hadron properties are expected to occur. The spectral distribution of virtual photons measured in Au+Au collisions at 2.4 GeV center of mass energy indicates strong medium effects beyond pure superposition of individual NN collisions. We present multi-differential distributions of low-mass electron pairs. This radiation is remarkably well described assuming emission from a thermalized system. To gain deeper understanding of the microscopic origin of the radiation, we extracted the centrality dependent true (not blue-shifted) temperature, its azimuthal distribution, as well as mass-dependent effective slope parameter. Virtual photon spectra are confronted with available model calculations.
Sub-threshold strangeness production measured with HADES
G. Kornakov, J. Adamczewski-Musch, O. Arnold, B. Arnoldi-Meadows, A. Belounnas, A. Belyaev, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, L. Chlad, P. Chudoba, I. Ciepal, C. Deveaux, D. Dittert, J. Dreyer, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, A. Gillitzer, O. Golosov, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, V. Ivanov, A. Ivashkin, B. Kampfer, M. Kajetanowicz, KH. Kampert, B. Kardan, V. Khomyakov, I. Koenig, W. Koenig, G. Korcyl, F. Kornas, R. Kotte, A. Kozela, J. Kubos, A. Kugler, T. Kunz, P. Kurilkin, V. Kushpil, V. Ladygin, R. Lalik, A. Lebedev, S. Linev, L. Lopes, M. Lorenz, G. Lykasov, T. Mahmoud, A. Malakhov, J. Markert, S. Maurus, V. Metag, et al.
abstract
At energies below root S-NN approximate to 2.55 GeV, strange quarks cannot be produced in binary nucleon-nucleon collisions because of the higher production threshold of the lightest hadrons carrying strangeness. Hence, the investigation of sub-threshold strangeness production in heavy-ion collisions is one of the most promising probes, to access the properties of the created system, as the missing energy must be provided by the latter one. For the first time, a nearly complete set of strange particles has been reconstructed in the 40% most central Au+Au collisions at. root S-NN = 2.42 GeV. The data sample includes multi-differential representations of charged and neutral particles containing strangeness (K-+/-,K-s(0), phi, Lambda). To achieve a better understanding of strangeness production the properties of the short-lived resonances have to be investigated. The first steps in this direction are presented here, including the reconstruction of baryon resonances using a new iterative technique, comparison to microscopic transport model calculations and interpretation of the pion transverse momentum distribution.
Time-Like Baryon Transitions studies with HADES
B. Ramstein, J. Adamczewski-Musch, O. Arnold, B. Arnoldi-Meadows, A. Belounnas, A. Belyaev, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, L. Chlad, P. Chudoba, I. Ciepal, C. Deveaux, D. Dittert, J. Dreyer, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, A. Gillitzer, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, M. Himmelreich, C. Hohne, R. Holzmann, A. Ierusalimov, V. Ivanov, A. Ivashkin, B. Kampfer, M. Kajetanowicz, KH. Kampert, T. Karavicheva, B. Kardan, V. Khomyakov, I. Koenig, W. Koenig, G. Korcyl, G. Kornakov, F. Kornas, R. Kotte, A. Kozela, J. Kubos, A. Kugler, T. Kunz, A. Kurepin, P. Kurilkin, V. Kushpil, V. Ladygin, R. Lalik, A. Lebedev, S. Linev, M. Liu, L. Lopes, M. Lorenz, G. Lykasov, et al.
abstract
The HADES collaboration uses the e(+)e(-) production as a probe of the resonance matter produced in collisions at incident energies of 1-3.5 GeV/nucleon at GSI. Elementary reactions provide useful references for these studies and give information on resonance Dalitz decays (R -> Ne(+)e(-)). Such processes are sensitive to the structure of time-like electromagnetic baryon transitions in a kinematic range where (off-shell) vector mesons play a crucial role. Results obtained in proton-proton reactions and in a commissioning pion-beam experiment are reported and prospects for future pion beam experiments and for first hyperon Dalitz decay measurements are described. The connection with the investigations of medium effects to be continued with HADES in the next years at SIS18 and SIS100 is also discussed.
Sigma(0) production in proton nucleus collisions near threshold
J. Adamczewski-Musch, G. Agakishiev, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, S. Maurus, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, et al.
abstract
The production of Sigma(0) baryons in the nuclear reaction p (3.5 GeV) + Nb (corresponding to root sNN = 3.18 GeV) is studied with the detector set-up HADES at GSI, Darmstadt. Sigma(0)s were identified via the decay Sigma 0 -> Lambda gamma with subsequent decays Lambda -> p pi(-) in coincidence with a e(+)e(-) pair from either external (gamma -> e(+)e(-)) or internal (Dalitz decay gamma* -> e(+)e(-)) gamma conversions. The differential Sigma(0) cross section integrated over the detector acceptance, i.e. the rapidity interval 0.5 < y < 1.1, has been extracted as Delta sigma(Sigma 0) = 2.3 +/- (0.2)(stat) +/- ((+0.6)(-0.6))(sys) +/- (0.2)(norm) mB, yielding the inclusive production cross section in full phase space sigma(total)(Sigma 0) = 5.8 +/- (0.5)(stat) +/- ((+1.4)(-1.4))(sys) +/- (0.6)(norm) +/- (1.7)(extrapol) mb by averaging over different extrapolation methods. The Lambda(all)/Sigma(0) ratio within the HADES acceptance is equal to 2.3 +/- (0.2)(stat) +/- ((+0.6)(-0.6))(sys). The obtained rapidity and momentum distributions are compared to transport model calculations. The Sigma(0) yield agrees with the statistical model of particle production in nuclear reactions. (C) 2018 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license.
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.
Centrality determination of Au plus Au collisions at 1.23A GeV with HADES
J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, et al.
abstract
The centrality determination for Au + Au collisions at 1.23 A GeV, as measured with HADES at the GSI-SIS18, is described. In order to extract collision geometry related quantities, such as the average impact parameter or number of participating nucleons, a Glauber Monte Carlo approach is employed. For the application of this model to collisions at this relatively low centre-of-mass energy of root sNN = 2.42 GeV special investigations were performed. As a result a well defined procedure to determine centrality classes for ongoing analyses of heavy-ion data is established.
Deep sub-threshold phi production in Au plus Au collisions
J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, R. Greifenhagen, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, et al.
abstract
We present data on charged kaons (K-+/-) and phi mesons in Au(1.23AGeV)+ Au collisions. It is the first simultaneous measurement of K- and phi mesons in central heavy-ion collisions below a kinetic beam energy of 10AGeV. The phi/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 +/- 0.16and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed-down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze-out temperatures of K+ and K- mesons caused by different couplings to baryons. (C) 2018 The Author(s). Published by Elsevier B.V.
A facility for pion-induced nuclear reaction studies with HADES
J. Adamczewski-Musch, O. Arnold, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, S. Morozov, C. Muntz, R. Munzer, et al.
abstract
The combination of a production target for secondary beams, an optimized ion optical beam line setting, in-beam detectors for minimum ionizing particles with high rate capability, and an efficient large acceptance spectrometer around the reaction target constitutes an experimental opportunity to study in detail hadronic interactions utilizing pion beams impinging on nucleons and nuclei. For the 0.4-2.0 GeV/c pion momentum regime such a facility is located at the heavy ion synchrotron accelerator SIS18 in Darm-stadt (Germany). The layout of the apparatus, performance of its components and encouraging results from a first commissioning run are presented.
Analysis of the exclusive final state npe(+)e(-) in the quasi-free np reaction
J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hoehne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, W. Kuehn, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, DM. Mihaylov, et al.
abstract
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u impinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of e(+)e(-) pairs above the pi(0) mass in the exclusive channel dp -> npe(+)e(-)(p(spect)) as compared to the exclusive channel ppe(+)e(-) measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double-Delta excitation combined with intermediate rho-meson production. Differential cross sections as a function of the e(+)e(-) invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical sides.
Delta (1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES at GSI
J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, A. Belounnas, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Boehmer, P. Bordalo, S. Chernenko, L. Chlad, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Filip, P. Finocchiaro, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Heinz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, S. Maurus, V. Metag, J. Michel, et al.
abstract
We report on the investigation of Delta(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels ppe(+) e(-) and ppe(+) e(-). have been studied and compared with the partial-wave analysis of the hadronic pp pi(0) channel. They allow to access both Delta(+) -> p pi(0)( e(+) e(-) gamma) and Delta(+) -> pe(+) e(-) Dalitz decay channels. The perfect reconstruction of the well-known pi(0) Dalitz decay serves as a proof of the consistency of the analysis. The Delta Dalitz decay is identified for the first time and the sensitivity to N-Delta transition form factors is tested. The Delta (1232) Dalitz decay branching ratio is also determined for the first time; our result is (4.19 +/- 0.62 syst. +/- 0.34 stat.) x 10(-5), albeit with some model dependence.
Inclusive Lambda production in proton-proton collisions at 3.5 GeV
J. Adamczewski-Musch, G. Agakishiev, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, J. Dreyer, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcy, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, S. Maurus, A. Mangiarotti, J. Markert, V. Metag, J. Michel, S. Morozov, C. Muntz, R. Munzer, et al.
abstract
The inclusive production of Lambda hyperons in proton-proton collisions at root s = 3.18 GeV was measured with HADES at the GSI Helmholtzzentrum fur Schwerionenforschung in Darmstadt. The experimental data are compared to a data- based model for individual exclusive Lambda production channels in the same reaction. The contributions of intermediate resonances such as Sigma(1385), Delta(++), or N-* are considered in detail. In particular, the result of a partial- wave analysis accounts for the abundant pK(+) Lambda final state. Model and data show a reasonable agreement at midrapidities, while a difference is found for larger rapidities. A total Lambda production cross section in p + p collisions at root s = 3.18 GeV of sigma (p + p -> Lambda + X) = 207.3 +/- 1.3 (+6.0) (-7.3)(stat.) +/- 8.4(syst.) (+ 0.4) (- 0.5)(model.) mu b is found.
Lambda p interaction studied via femtoscopy in p plus Nb reactions at root s(NN)=3.18 GeV
J. Adamczewski-Musch, G. Agakishiev, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, S. Maurus, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, et al.
abstract
We report on the first measurement of p Lambda and pp correlations via the femtoscopy method in p + Nb reactions at root sNN = 3.18 GeV, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for pp pairs of r(0,pp) = 2.02 +/- 0.01(stat)(-0.12)(+0.11)(sys) fm and a slightly smaller value for p Lambda pairs of r(0,Lambda p) = 1.62 +/- 0.02(stat)(-0.08)(+0.19)(sys) fm are extracted. Using the geometrical extent of the particle-emitting region, determined experimentally with pp correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The p Lambda correlation is proven to be sensitive to predicted scattering length values from chiral effective field theory. We demonstrate that the femtoscopy technique can be used as a valid alternative to the analysis of scattering data to study the hyperon-nucleon interaction.
Statistical hadronization model analysis of hadron yields in p plus Nb and Ar plus KCl at SIS18 energies
G. Agakishiev, O. Arnold, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, E. Castro, S. Chernenko, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, C. Gilardi, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, JS. Lange, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, D. Mihaylov, J. Michel, et al.
abstract
The HADES data from p + Nb collisions at a center-of-mass energy of root s(NN) = 3.2 GeV are analyzed employing a statistical hadronization model. The model can successfully describe the production yields of the identified hadrons pi(0), eta, Lambda, K-s(0), omega with parameters T-chem = (99 +/- 11) MeV and mu(b) = (619 +/- 34) MeV, which fit well into the chemical freeze-out systematics found in heavy-ion collisions. In addition, we reanalyze our previous HADES data from Ar + KCl collisions at root s(NN) = 2.6 GeV with an updated version of the model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit as a function of colliding energy and system size. Despite its success, the model fails to describe the observed Xi(-) yields in both, p + Nb and Ar + KCl. Special emphasis is put on feed-down contributions from higher-lying resonance states as a possible explanation for the observed excess.
Strange hadron production at SIS energies: an update from HADES
M. Lorenz, J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, et al.
abstract
We present and discuss recent experimental activities of the HADES collaboration on open and hidden strangeness production close or below the elementary NN threshold. Special emphasis is put on the feed-down from phi mesons to antikaons, the presence of the Xi(-) excess in cold nuclear matter and the comparison of statistical model rates to elementary p+p data. The implications for the interpretation of heavy-ion data are discussed as well.
Analysis of pion production data measured by HADES in proton-proton collisions at 1.25 GeV
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, R. Munzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
Baryon resonance production in proton-proton collisions at a kinetic beam energy of 1.25 GeV is investigated. The multi-differential data were measured by the HADES Collaboration. Exclusive channels with one pion in the final state (np pi(+) and pp pi(0)) were put to extended studies based on various observables in the framework of a one-pion exchange model and with solutions obtained within the framework of a partial wave analysis (PWA) of the Bonn-Gatchina group. The results of the PWA confirm the dominant contribution of the.(1232), yet with a sizable impact of the N(1440) and non-resonant partial waves.
K*(892)(+) production in proton-proton collisions at E-beam=3.5 GeV
G. Agakishiev, O. Arnold, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frolich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, D. Mihaylov, C. Muntz, R. Munzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
We present results on the K*(892)(+) production in proton-proton collisions at a beam energy of E = 3.5 GeV, which is hitherto the lowest energy at which this mesonic resonance has been observed in nucleon-nucleon reactions. The data are interpreted within a two-channel model that includes the three-body production of K*(892)(+) associated with the Lambda or Sigma hyperon. The relative contributions of both channels are estimated. Besides the total cross section sigma(p + p -> K*(892)(+) + X) = 9.5 +/- 0.9(-0.9)(+1.1) +/- 0.7 mu b, which adds a new data point to the excitation function of the K*(892)+ production in the region of low excess energy, transverse momenta and angular spectra are extracted and compared with the predictions of the two-channel model. The spin characteristics of K*(892)(+) are discussed as well in terms of the spin-alignment.
Subthreshold Xi(-) Production in Collisions of p(3.5 GeV) + Nb
G. Agakishiev, O. Arnold, A. Balanda, D. Belver, AV. Belyaev, JC. Berger-Chen, A. Blanco, M. Bhmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, OV. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, R. Muntzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, et al.
abstract
Results on the production of the double strange cascade hyperon Xi(-) are reported for collisions of p(3.5 GeV) + Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. For the first time, subthreshold Xi(-) production is observed in proton-nucleus interactions. Assuming a Xi(-) phase-space distribution similar to that of. hyperons, the production probability amounts to P Xi- = [2.0 +/- 0.4(stat) +/- 0.3(norm) +/- 0.6(syst)] x 10(-4) resulting in a Xi(-)/d(Lambda + Sigma(0)) ratio of P Xi-/P Lambda+Sigma 0 = [1.2 +/- 0.3(stat) +/- 0.4(syst)] x 10(-2). Available model predictions are significantly lower than the measured Xi(-) yield.
Partial wave analysis of the reaction p(3.5 GeV) + p -> pK(+) Lambda to search for the "ppK(-)" bound state
G. Agakishiev, O. Arnold, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntzh, R. Muenzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, J. Pietraszko, et al.
abstract
Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5 GeV) + p -> pK(+) Lambda. This reaction might contain information about the kaonic cluster "ppK(-)" (with quantum numbers J(P)=0(-) and total isospin I=1/2) via its decay into p Lambda. Due to interference effects in our coherent description of the data, a hypothetical (K) over bar NN(or, specifically "ppK-") cluster signal need not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectrum like p Lambda. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a (K) over bar NN cluster. At a confidence level of CLs=95% such a cluster cannot-contribute more than 2-12% to the total cross section with a pK(+) Lambda final state, which translates into a production cross-section between 0.7 mu b and 4.2 mu b, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.
Highlights of Resonance Measurements With HADES
E. Epple, J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, K. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, et al.
abstract
This contribution aims to give a basic overview of the latest results regarding the production of resonances in different collision systems. The results were extracted from experimental data collected with HADES that is a multipurpose detector located at the GSI Helmholtzzentrum, Darmstadt. The main points discussed here are: the properties of the strange resonances Lambda(1405) and Sigma(1385), the role of Delta's as a source of pions in the final state, the production dynamics reflected in form of differential cross sections, and the role of the phi meson as a source for K- particles.
Investigating hadronic resonances in pp interactions with HADES
W. Przygoda, J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlavac, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, B. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, et al.
abstract
In this paper we report on the investigation of baryonic resonance production in proton-proton collisions at the kinetic energies of 1.25 GeV and 3.5 GeV, based on data measured with HADES. Exclusive channels np pi(+) and ppp(0) as well as ppe(+) e(-) were studied simultaneously in the framework of a one-boson exchange model. The resonance cross sections were determined from the one-pion channels for Delta(1232) and N(1440) (1.25 GeV) as well as further Delta and N* resonances up to 2 GeV/c(2) for the 3.5 GeV data. The data at 1.25 GeV energy were also analysed within the framework of the partial wave analysis together with the set of several other measurements at lower energies. The obtained solutions provided the evolution of resonance production with the beam energy, showing a sizeable non-resonant contribution but with still dominating contribution of Delta(1232)P-33. In the case of 3.5 GeV data, the study of the ppe(+)e(-) channel gave the insight on the Dalitz decays of the baryon resonances and, in particular, on the electromagnetic transition form-factors in the time-like region. We show that the assumption of a constant electromagnetic transition form-factors leads to underestimation of the yield in the dielectron invariant mass spectrum below the vector mesons pole. On the other hand, a comparison with various transport models shows the important role of intermediate rho production, though with a large model dependency. The exclusive channels analysis done by the HADES collaboration provides new stringent restrictions on the parameterizations used in the models.
Medium effects in proton-induced K-0 production at 3.5 GeV
G. Agakishiev, O. Arnold, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumbcridzc, T. Hcinz, T. Hcnnino, R. Holzmann, A. Icrusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
We present the analysis of the inclusive K-0 production in p + p and p + Nb collisions measured with the HADES detector (GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt) at a beam kinetic energy of 3.5 GeV. Data are compared to the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model. The data suggest the presence of a repulsive momentum-dependent kaon potential as predicted by the chiral perturbation theory (ChPT). For the kaon at rest and at normal nuclear density, the ChPT potential amounts to approximate to 35 MeV. A detailed tuning of the kaon production cross sections implemented in the model has been carried out to reproduce the experimental data measured in p + p collisions. The uncertainties in the parameters of the model were examined with respect to the sensitivity of the experimental results from p + Nb collisions to the in-medium kaon potential.
Time of flight measurement in heavy-ion collisions with the HADES RPC TOF wall
G. Kornakov, I. Arnold, ET. Atomssa, C. Behnke, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, K. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, V. Pechenov, O. Pechenova, V. Petousis, et al.
abstract
This work presents the analysis of the performance of the RPC ToF wall of the HADES, located at GSI Helmholtzzentrum fur Schwerionenforschung, Darmstadt. The behavior of the detector is studied in Au+Au collisions at 1.23 AGeV. A main characteristic of the detector is that all the active areas were designed to be electrically shielded in order to operate in high occupancies of the chambers. Here we show the achieved performance regarding efficiency and timing capabilities at different occupancies of this special design after the applied offline corrections to the data. Also the stability of the intrinsic time resolution over time of data taking is presented.
Associate K-0 production in p plus p collisions at 3.5 GeV: The role of Delta(1232)(++)
G. Agakishiev, O. Arnold, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, T. Kunz, A. Kurepin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
An exclusive analysis of the four-body final states Lambda + p + pi(+) + K-0 and Sigma(0) + p + pi(+) + K-0 measured with HADES for p + p collisions at a beam kinetic energy of 3.5 GeV is presented. The analysis uses various phase space variables, such as missing mass and invariant mass distributions, in the four-particle event selection (p,pi(+),pi(+),pi(-)) to find cross sections of the different production channels, contributions of the intermediate resonances Delta(++) and Sigma(1385)(+), and corresponding angular distributions. A dominant resonant production is seen, where the reaction Lambda + Delta(++) + K-0 has a cross section about ten times higher (29.45 +/- 0.08(-1.46)(+1.67) +/- 2.06 mu b) than the analogous nonresonant reaction (2.57 +/- 0.02(-1.98)(+0.21) +/- 0.18 mu b). A similar result is obtained in the corresponding Sigma(0) channels with 9.26 +/- 0.05(-0.31)(+1.41) +/- 0.65 mu b in the resonant and 1.35 +/- 0.02(-1.35)(+0.10) +/- 0.09 mu b in the nonresonant reactions.
Lambda hyperon production and polarization in collisions of p(3.5 GeV)+Nb
G. Agakishiev, O. Arnold, A. Balanda, D. Belver, AV. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, OV. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, et al.
abstract
Results on. hyperon production are reported for collisions of p(3.5 GeV) + Nb, studied with the High-Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. The transverse mass distributions in rapidity bins are well described by Boltzmann shapes with a maximum inverse slope parameter of about 90 MeV at a rapidity of y = 1.0, i.e. slightly below the center-of-mass rapidity for nucleon-nucleon collisions, y(cm) = 1.12. The rapidity density decreases monotonically with increasing rapidity within a rapidity window ranging from 0.3 to 1.3. The Lambda phase-space distribution is compared with results of other experiments and with predictions of two transport approaches which are available publicly. None of the present versions of the employed models is able to fully reproduce the experimental distributions, i.e. in absolute yield and in shape. Presumably, this finding results from an insufficient modelling in the transport models of the elementary processes being relevant for Lambda production, rescattering and absorption. The present high-statistics data allow for a genuine two-dimensional investigation as a function of phase space of the self-analyzing Lambda polarization in the weak decay Lambda -> p pi(-). Finite negative values of the polarization in the order of 5-20% are observed over the entire phase space studied. The absolute value of the polarization increases almost linearly with increasing transverse momentum for p(t) > 300 MeV/c and increases with decreasing rapidity for y < 0.8.
Baryon resonance production and dielectron decays in proton-proton collisions at 3.5 GeV
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
We report on baryon resonance production and decay in proton-proton collisions at a kinetic energy of 3.5 GeV based on data measured with HADES. The exclusive channels pp -> np pi(+) and pp -> pp pi(0) as well as pp -> ppe(+)e(-) are studied simultaneously for the first time. The invariant masses and angular distributions of the pion-nucleon systems were studied and compared to simulations based on a resonance model ansatz assuming saturation of the pion production by an incoherent sum of baryonic resonances (R) with masses < 2 GeV/c(2). A very good description of the one-pion production is achieved allowing for an estimate of individual baryon resonance production cross sections which are used as input to calculate the dielectron yields from R -> pe(+)e(-) decays. Two models of the resonance decays into dielectrons are examined assuming a point-like RN gamma* coupling and the dominance of the rho meson. The results of model calculations are compared to data from the exclusive ppe(+)e(-) channel by means of the dielectron and pe(+)e(-) invariant mass distributions.
Searching a dark photon with HADES
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
We present a search for the e(+)e(-) decay of a hypothetical dark photon, also named U vector boson, in inclusive dielectron spectra measured by HADES in the p(3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) KCl reaction. An upper limit on the kinetic mixing parameter squared epsilon(2) at 90% CL has been obtained for the mass range M-U = 0.02-0.55 GeV/c(2) and is compared with the present world data set. For masses 0.03-0.1 GeV/c(2), the limit has been lowered with respect to previous results, allowing now to exclude a large part of the parameter region favored by the muon g - 2 anomaly. Furthermore, an improved upper limit on the branching ratio of 2.3 x 10(-6) has been set on the helicity-suppressed direct decay of the eta meson, eta --> e(+)e(-), at 90% CL. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license
Measurement of the quasi free np -> np pi(+)pi(-) and np -> pp pi(-)pi(0) reactions at 1.25 GeV with HADES
A. Kurilkin, O. Arnold, ET. Atomssa, C. Behnke, A. Belyaev, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, K. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Ku, A. Kugler, T. Kunz, A. Kurepin, P. Kurilkine, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, V. Pechenov, O. Pechenova, et al.
abstract
We present the results of two-pion production in tagged quasi-free np collisions at a deutron incident beam energy of 1.25 GeV/c measured with the High-Acceptance Di-Electron Spectrometer (HADES) installed at GSI. The specific acceptance of HADES allowed for the first time to obtain high-precision data on pi(+)pi(-) and pi(-)pi(0) production in np collisions in a region corresponding to large transverse momenta of the secondary particles. The obtained differential cross section data provide strong constraints on the production mechanisms and on the various baryon resonance contributions (Delta Delta, N(1440), N(1520), Delta(1600)). The invariant mass and angular distributions from the np -> np pi(+)pi(-) and np -> pp pi(-)pi(0) reactions are compared with different theoretical model predictions.
HADES results in elementary reactions
B. Ramstein, J. Adamczewski-Musch, O. Arnold, ET. Atomssa, C. Behnke, JC. Berger-Chen, J. Biernat, A. Blanco, C. Blume, M. Bohmer, P. Bordalo, S. Chernenko, C. Deveaux, A. Dybczake, E. Epple, L. Fabbietti, O. Fateev, P. Fonteb, C. Franco, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, S. Hlava, C. Hohne, R. Holzmann, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, K. Kardan, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, H. Kuc, A. Kugler, T. Kunz, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, T. Mahmoud, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, et al.
abstract
Recent results obtained with the HADES experimental set-up at GSI are presented with a focus on dielectron production and strangeness in pp and quasi-free np reactions. Perspectives related to the very recent experiment using the pion beam at GSI are also discussed.
Low mass dielectrons radiated off cold nuclear matter measured with HADES
M. Lorenz, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, S. Chernenko, C. Dritsa, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, C. Hohne, R. Holzmann, P. Huck, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, J. Pietraszko, et al.
abstract
The High Acceptance DiElectron Spectrometer HADES [1] is installed at the Helmholtzzentrum fur Schwerionenforschung (GSI) accelerator facility in Darmstadt. It investigates dielectron emission and strangeness production in the 1-3 AGeV regime. A recent experiment series focusses on medium-modifications of light vector mesons in cold nuclear matter. In two runs, p + p and p + Nb reactions were investigated at 3.5 GeV beam energy; about 9 . 10(9) events have been registered. In contrast to other experiments the high acceptance of the HADES allows for a detailed analysis of electron pairs with low momenta relative to nuclear matter, where modifications of the spectral functions of vector mesons are predicted to be most prominent. Comparing these low momentum electron pairs to the reference measurement in the elementary p + p reaction, we find in fact a strong modification of the spectral distribution in the whole vector meson region.
In-medium hadron properties measured with HADES
J. Pietraszko, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, S. Chernenko, C. Dritsa, A. Dybczak, E. Epples, L. Fabbietti, O. Fateev, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, C. Hohne, R. Holzmann, P. Huck, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
Many QCD based and phenomenological models predict changes of hadron properties in a strongly interacting environment. The results of these models differ significantly and the experimental determination of hadron properties in nuclear matter is essential. In this paper we present a review of selected physics results obtained at GSI Helmholtzzentrum fur Schwerionenforschung GmbH by HADES (High-Acceptance Di-Electron Spectrometer). The e(+)e(-) pair emission measured for proton and heavy-ion induced collisions is reported together with results on strangeness production. The future HADES activities at the planned FAIR facility are also discussed.
pK(+)Lambda final state: Towards the extraction of the ppK(-) contribution
L. Fabbietti, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, S. Chernenko, C. Dritsa, A. Dybczak, E. Epple, O. Fateev, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, C. Hohne, R. Holzmann, P. Huck, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, J. Pietraszko, et al.
abstract
The reaction p(@3.5 GeV) + p -> p + Lambda + K+ can be studied to search for the existence of kaonic bound states like ppK(-) leading to this final state. This effort has been motivated by the assumption that in p + p collisions the Lambda(1405) resonance can act as a doorway to the formation of the kaonic bound states. The status of this analysis within the HADES Collaboration, with particular emphasis on the comparison to simulations, is shown in this work and the deviation method utilized by the DISTO Collaboration in a similar analysis is discussed. The outcome suggests the employment of a partial wave analysis do disentangle the different contributions to the measured pK(+)Lambda final state. (c) 2013 Elsevier B.V. All rights reserved.
Inclusive pion and eta production in p plus Nb collisions at 3.5 GeV beam energy
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, C. Muntz, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
Data on inclusive pion and eta production measured with the dielectron spectrometer HADES in the reaction p + Nb-93 at a kinetic beam energy of 3.5 GeV are presented. Our results, obtained with the photon-conversion method, supplement the rather sparse information on neutral-meson production in proton-nucleus reactions existing for this bombarding energy regime. The reconstructed e(+)e(-)e(+)e(-) transverse-momentum and rapidity distributions are confronted with transport-model calculations, which account fairly well for both pi(0) and eta production.
Baryonic resonances close to the (K)over-barN threshold: The case of Lambda (1405) in pp collisions
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, E. Castro, S. Chernenko, T. Christ, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, C. Gilardi, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, K. Kanaki, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, R. Lalik, S. Lang, JS. Lange, K. Lapidus, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, E. Moriniere, J. Mousa, C. Muntz, R. Munzer, L. Naumann, et al.
abstract
We present an analysis of the Lambda(1405) resonance produced in the reaction p + p -> Sigma(+/-) + pi(-/+) + K+ + p at 3.5 GeV kinetic beam energy measured with the High Acceptance Dielectron Spectrometer (HADES) at the Gesellschaft fur Schwerionenforschung (GSI). The two charged decay channels Lambda (1405) -> Sigma(+/-) + pi(-/+) have been reconstructed for the first time in p + p collisions. The efficiency and acceptance- corrected spectral shapes show a peak position clearly below 1400MeV/c(2). We find a total production cross section of sigma(Lambda(1405)) = (1405) = 9.2 +/- 0.9 +/- 0.7(-1.0)(+3.3)mu b . The analysis of its polar angle distribution suggests that the Lambda(1405) is produced isotropically in the p - p center-of-mass system (CMS). DOI: 10.1103/ PhysRevC.87.025201
Hades experiments: investigation of hadron in-medium properties
P. Salabura, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, S. Chernenko, C. Dritsa, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, R. Holzmann, P. Huck, C. Hohne, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, et al.
abstract
Hadron modifications in nuclear matter are discussed in connection to chiral symmetry restoration and/or hadronic many body effects. Experiments with photon, proton and heavy ion beams are used to probe properties of hadrons embedded in nuclear matter at different temperatures and densities. Most of the information has been gathered for the light vector mesons rho, omega and phi. HADES is a second generation experiment operating at GSI with the main aim to study in-medium modifications by means of dielectron production at the SIS18/Bevelac energy range. Large acceptance and excellent particle identification capabilities allows also for measurements of strangeness production. These abilities combined with the variety of beams provided by the SIS18 allow for a characterization of properties of the dense baryonic matter properties created in heavy ion collisions at these energies. A review of recent experimental results obtained by HADES is presented, with main emphasis on hadron properties in nuclear matter.
First measurement of proton-induced low-momentum dielectron radiation off cold nuclear matter
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, S. Chernenko, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, K. Gobelg, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Kornakov, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, D. Mishra, C. Muntz, L. Naumann, YC. Pachmayer, M. Palka, Y. Parpottas, V. Pechenov, et al.
abstract
We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e(+)e(-) invariant mass spectra to elementary p + p data, we observe for e(+)e(-) momenta P-ee < 0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional rho-like contribution and a decrease of omega yield. These opposite trends are tentatively interpreted as a strong coupling of the rho meson to baryonic resonances and an absorption of the omega meson, which are two aspects of in-medium modification of vector mesons. (c) 2012 Elsevier B.V. All rights reserved.
Production of Sigma(+/-)pi(-/+)pK(+) in p plus p reactions at 3.5 GeV beam energy
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, E. Castro, S. Chernenko, T. Christ, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, C. Gilardi, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, K. Kanaki, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, R. Lalik, S. Lang, JS. Lange, K. Lapidus, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, E. Moriniere, J. Mousa, C. Muntz, R. Munzer, L. Naumann, et al.
abstract
We study the production of Sigma(+/-)pi(-/+)-pK(+) particle quartets in p + p reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES experiment at GSI. This report evaluates the contribution of resonances like Lambda(1405), Sigma(1385)(0), Lambda(1520), Delta(1232), N* and K*(0) to the Sigma(+/-)pi(-/+)pK(+) final state. The resulting simulation model is compared to the experimental data in several angular distributions and it shows itself as suitable to evaluate the acceptance corrections properly. (C) 2012 Elsevier B.V. All rights reserved.
Inclusive dielectron spectra in p plus p collisions at 3.5 GeV kinetic beam energy
G. Agakishiev, H. Collaboration, A. Balanda, D. Belver, A. Belyaev, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, E. Castro, JC. Chen, S. Chernenko, T. Christ, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, C. Gilardi, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, K. Kanaki, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, R. Lalik, S. Lang, JS. Lange, K. Lapidus, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, E. Moriniere, J. Mousa, C. Muntz, L. Naumann, et al.
abstract
We present the inclusive invariant mass, transverse momentum and rapidity distributions of dielectrons (e(+)e(-) pairs) in p+p interactions at 3.5 GeV beam kinetic energy. In the vector meson mass region, a distinct peak corresponding to direct omega decays is reconstructed with a 2% mass resolution. The data is compared to predictions from three model calculations. Due to the large acceptance of the HADES apparatus for e(+)e(-) invariant masses above 0.2 GeV/c(2) and for transverse pair momenta p(t) < 1 GeV/c, acceptance corrections are, to a large extent, model independent. This allows us to extract from dielectron data for the first time at this energy the inclusive production cross-sections for light vector mesons. Inclusive production cross-sections for pi(0) and eta mesons are also reported. The obtained results will serve as an important reference for the study of vector meson production in proton-nucleus and heavy-ion collisions. Furthermore, using this data, an improved value for the upper bound of the branching ratio for direct eta decays into the electron-positron channel is obtained.
The HADES-at-FAIR project
K. Lapidus, G. Agakishiev, A. Balanda, R. Bassini, C. Behnke, A. Belyaev, A. Blanco, M. Bohmer, P. Cabanelas, N. Carolino, JC. Chen, S. Chernenko, J. Diaz, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, A. Gil, K. Gobel, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, K. Heidel, T. Heinz, T. Hennino, R. Holzmann, P. Huck, J. Hutsch, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, B. Kampfer, M. Kajetanowicz, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Kozuch, E. Krebs, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, JS. Lange, M. Liu, T. Liu, L. Lopes, M. Lorenz, G. Lykasov, L. Maier, A. Malakhov, A. Mangiarotti, et al.
abstract
After the completion of the experimental program at SIS18 the HADES setup will migrate to FAIR, where it will deliver high-quality data for heavy-ion collisions in an unexplored energy range of up to 8 A GeV. In this contribution, we briefly present the physics case, relevant detector characteristics and discuss the recently completed upgrade of HADES.
Baryonic resonances close to the (K)over-bar N threshold: The case of Sigma(1385)(+) in pp collisions
G. Agakishiev, A. Balanda, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, M. Bohmer, JL. Boyard, P. Cabanelas, E. Castro, S. Chernenko, T. Christ, M. Destefanis, F. Dohrmann, A. Dybczak, E. Epple, L. Fabbietti, OV. Fateev, P. Finocchiaro, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, R. Gernhauser, C. Gilardi, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, T. Heinz, T. Hennino, R. Holzmann, A. Ierusalimov, I. Iori, A. Ivashkin, M. Jurkovic, BK. Ampfer, K. Kanaki, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, R. Kotte, A. Krasa, F. Krizek, R. Krucken, H. Kuc, W. Kuhn, A. Kugler, A. Kurepin, R. Lalik, S. Lang, JS. Lange, K. Lapidus, T. Liu, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, B. Michalska, J. Michel, E. Moriniere, J. Mousa, C. Muntz, L. Naumann, J. Otwinowski, et al.
abstract
We present results of an exclusive measurement of the first-excited state of the Sigma hyperon, Sigma(1385)(+), produced in p + p -> Sigma(+) + K+ + n at 3.5 GeV beam energy. The extracted data allow the detailed study of the invariant mass distribution of the Sigma(1385)(+). The mass distribution is well described by a relativistic Breit-Wigner function with a maximum at m(0) = 1383.2 +/- 0.9 MeV/c(2) and a width of 40.2 +/- 2.1 MeV/c(2). The exclusive production cross section comes out to be 22.27 +/- 0.89 +/- 1.56(-2.10)(+3.07) mu b. Angular distributions of the Sigma(1385)(+) in different reference frames are found to be compatible with the hypothesis that 33% of Sigma(1385)(+) result from the decay of an intermediate broad Delta(++) excitation at about 2000 MeV/c(2).
The dp-elastic cross section measurement at the deuteron kinetic energy of 2.5 GeV
P. Kurilkin, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, S. Chernenko, C. Dritsa, A. Dybczak, E. Epple, L. Fabbietti, O. Fateev, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, R. Holzmann, P. Huck, C. Hohne, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, M. Lorenz, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, J. Pietraszko, et al.
abstract
New results on the differential cross section in deuteron-proton elastic scattering are obtained at the deuteron kinetic energy of 2.5 GeV with the HADES spectrometer. The angular range of 69 degrees - 125 degrees in the center of mass system is covered. The obtained results are compared with the relativistic multiple scattering model calculation using the CD-Bonn deuteron wave function. The data at fixed scattering angles in the c.m. are in qualitative agreement with the constituent counting rules prediction.
Resonance production in p plus p, p plus A and A plus A collisions measured with HADES
M. Lorenz, G. Agakishiev, C. Behnke, D. Belver, A. Belyaev, JC. Berger-Chen, A. Blanco, C. Blume, M. Bohmer, P. Cabanelas, C. Dritsa, A. Dybczak, E. Epple, L. Fabbietti, P. Fonte, J. Friese, I. Frohlich, T. Galatyuk, JA. Garzon, K. Gill, M. Golubeva, D. Gonzalez-Diaz, F. Guber, M. Gumberidze, S. Harabasz, T. Hennino, R. Holzmann, P. Huck, C. Hohne, A. Ierusalimov, A. Ivashkin, M. Jurkovic, B. Kampfer, T. Karavicheva, I. Koenig, W. Koenig, BW. Kolb, G. Korcyl, G. Kornakov, R. Kotte, A. Krasa, E. Krebs, F. Krizek, H. Kuc, A. Kugler, A. Kurepin, A. Kurilkin, P. Kurilkin, V. Ladygin, R. Lalik, S. Lang, K. Lapidus, A. Lebedev, L. Lopes, L. Maier, A. Mangiarotti, J. Markert, V. Metag, J. Michel, C. Muntz, R. Munzer, L. Naumann, M. Palka, Y. Parpottas, V. Pechenov, O. Pechenova, J. Pietraszko, W. Przygoda, B. Ramstein, et al.
abstract
The knowledge of baryonic resonance properties and production cross sections plays an important role for the extraction and understanding of medium modifications of mesons in hot and/or dense nuclear matter. We present and discuss systematics on dielectron and strangeness production obtained with HADES on p+p, p+A and A+A collisions in the few GeV energy regime with respect to these resonances.
