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

TitleDeep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV
Publication TypeJournal Article
Year of Publication2013
AuthorsAgakishiev, G., A. Balanda, R. Bassini, D. Belver, A. V. Belyaev, A. Blanco, M. Bohmer, J. L. Boyard, P. Cabanelas, E. Castro et al.
JournalEuropean Physical Journal A
Date PublishedMar
ISBN Number1434-6001
Accession NumberWOS:000317855000006
AbstractResults 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.
URL<Go to ISI>://WOS:000317855000006
Short TitleDeep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV
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