Deep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV

0392915 - ÚJF 2014 RIV US eng J - Článek v odborném periodiku
Agakishiev, G. - Balanda, A. - Bassini, R. - Belver, D. - Belyaev, A. V. - Blanco, A. - Böhmer, M. - Boyard, J. L. - Cabanelas, P. - Castro, E. - Chernenko, S. - Christ, T. - Destefanis, M. - Díaz, J. - Dohrmann, F. - Křížek, Filip - Kugler, Andrej - Sobolev, Yuri, G. - Tlustý, Pavel - Wagner, Vladimír … celkem 103 autorů
Deep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV.
European Physical Journal A. Roč. 49, č. 3 (2013), s. 34. ISSN 1434-6001. E-ISSN 1434-601X
Grant CEP: GA MŠMT LC07050; GA AV ČR IAA100480803
Institucionální podpora: RVO:61389005
Klíčová slova: HADES * sub-treshold production
Kód oboru RIV: BG - Jaderná, atomová a mol. fyzika, urychlovače
Impakt faktor: 2.421, rok: 2013
http://link.springer.com/content/pdf/10.1140%2Fepja%2Fi2013-13034-7.pdf

Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)(0) are reported for collisions of Ar + KCl at 1.76 A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)(0) production probability per central collision of P-K*0 = (4.4 +/- 1.1 +/- 0.5) x 10(-4) and the K*(892)(0)/K-0 ratio of P-K*0/P-K0 = (1.9 +/- 0.5 +/- 0.3) x 10(-2) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, root s(NN)-root s(thr) = -340MeV). The K*(0)/K-0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K*(0) yield and the K-*0/K-0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K* production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium.
Trvalý link: http://hdl.handle.net/11104/0221700