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

Collaboration
2013
7 pages
Published in:
  • Eur.Phys.J.A 49 (2013) 34
Experiments:

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Abstract: (Springer)
Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)(0) are reported for collisions of Ar + KCl at 1.76A 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 and the K*(892)(0)/K(0) ratio of are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, MeV). 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. PDF = http://www.springerlink.com/
  • K*(892)0: hadroproduction
  • model: statistical
  • hadronization: model
  • transport theory
  • HADES
  • heavy ion: scattering
  • threshold
  • argon
  • potassium: chlorine
  • Darmstadt SIS