Abstract.
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 \( P_{K^{*0}}=(4.4\pm 1.1 \pm 0.5)\times 10^{-4}\) and the K*(892)0/K0 ratio of \( P_{K^{*0}}/P_{K^0}=(1.9\pm 0.5\pm 0.3)\times 10^{-2}\) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, \( \sqrt{s_{NN}}-\sqrt{s_{thr}}=-340\) MeV). The K*0/K0 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/K0 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.
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References
Particle Data Group (K. Nakamura et al.), J. Phys. G Nucl. Part. Phys. 37, 075021 (2010)
G. Torrieri, J. Rafelski, Phys. Rev. C 75, 024902 (2007)
F. Becattini, J. Manninen, M. Gazdzicki, Phys. Rev. C 73, 044905 (2006)
J. Randrup, J. Cleymans, Phys. Rev. C 74, 047901 (2006)
A. Andronic, P. Braun-Munzinger, J. Stachel, Nucl. Phys. A 772, 167 (2006)
S. Wheaton, J. Cleymans, Comput. Phys. Commun. 180, 84 (2009)
K. Tsushima, A. Sibirtsev, A.W. Thomas, Phys. Rev. C 62, 064904 (2000)
HADES Collaboration (G. Agakishiev et al.), Phys. Rev. C 82, 044907 (2010)
C. Hartnack, H. Oeschler, Y. Leifels, E.L. Bratkovskaya, J. Aichelin, Phys. Rep. 510, 119 (2012)
C. Blume, C. Markert, Prog. Part. Nucl. Phys. 66, 834 (2011)
ALICE Collaboration (B. Abelev et al.), Eur. Phys. J. C 72, 2183 (2012)
STAR Collaboration (J. Adams et al.), Phys. Rev. C 71, 064902 (2005)
STAR Collaboration (M.M. Aggarwal et al.), Phys. Rev. C 84, 034909 (2011)
NA49 Collaboration (T. Anticic et al.), Phys. Rev. C 84, 064909 (2011)
S.A. Bass et al., Prog. Part. Nucl. Phys. 41, 255 (1998)
M. Bleicher et al., J. Phys. G 25, 1859 (1999)
FOPI Collaboration (X. Lopez et al.), Phys. Rev. C 81, 061902 (2010)
HADES Collaboration (G. Agakichiev et al.), Phys. Rev. Lett. 98, 052302 (2007)
A. Schmah, PhD thesis, Techn. Universität Darmstadt (2008)
HADES Collaboration (G. Agakishiev et al.), Phys. Rev. C 80, 025209 (2009)
HADES Collaboration (G. Agakishiev et al.), Phys. Rev. Lett. 103, 132301 (2009)
HADES Collaboration (G. Agakishiev et al.), Eur. Phys. J. A 47, 21 (2011)
HADES Collaboration (G. Agakichiev et al.), Eur. Phys. J. A 41, 243 (2009)
HADES Collaboration (G. Agakishiev et al.), Phys. Rev. C 84, 014902 (2011)
HADES Collaboration (P. Tlusty), in Proceedings of the XLVII International Winter Meeting on Nuclear Physics, Bormio, Italy, Jan 26-30, 2009, arXiv:0906.2309 (2009)
HADES Collaboration (G. Agakishiev et al.), Eur. Phys. J. A 40, 45 (2009)
I. Fröhlich et al., Proc. Sci. PoS(ACAT), 076 (2007)
FOPI Collaboration (W. Reisdorf et al.), Nucl. Phys. A 848, 366 (2010)
KaoS Collaboration (A. Förster et al.), Phys. Rev. C 75, 024906 (2007)
GEANT 3.21, http://consult.cern.ch/writeup/geant/ (1993)
E.L. Bratkovskaya, M. Bleicher, M. Reiter, S. Soff, H. Stöcker, M. van Leeuwen, S.A. Bass, W. Cassing, Phys. Rev. C 69, 054907 (2004)
W. Cassing, E.L. Bratkovskaya, S. Juchem, Nucl. Phys. A 674, 249 (2000)
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The HADES Collaboration., Agakishiev, G., Balanda, A. et al. Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76 A GeV. Eur. Phys. J. A 49, 34 (2013). https://doi.org/10.1140/epja/i2013-13034-7
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DOI: https://doi.org/10.1140/epja/i2013-13034-7