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

G. Agakishiev; A. Balanda; R. Bassini; D. Belver; A. V. Belyaev; A. Blanco; M. Böhmer; J. L. Boyard; P. Cabanelas; E. Castro; S. Chernenko; T. Christ; M. Destefanis; J. Díaz; F. Dohrmann; A. Dybczak; T. Eberl; E. Epple; L. Fabbietti; O. V. Fateev; P. Finocchiaro; P. Fonte; J. Friese; I. Fröhlich; T. Galatyuk; J. A. Garzón; R. Gernhäuser; A. Gil; C. Gilardi; M. Golubeva; D. González-Díaz; F. Guber; M. Gumberidze; M. Heilmann; T. Heinz; T. Hennino; R. Holzmann; P. Huck; I. Iori; A. Ivashkin; M. Jurkovic; B. Kämpfer; K. Kanaki; T. Karavicheva; D. Kirschner; I. Koenig; W. Koenig; B. W. Kolb; R. Kotte; F. Krizek; R. Krücken; W. Kühn; A. Kugler; A. Kurepin; S. Lang; J. S. Lange; K. Lapidus; T. Liu; L. Lopes; M. Lorenz; L. Maier; A. Mangiarotti; J. Markert; V. Metag; B. Michalska; J. Michel; D. Mishra; E. Morinière; J. Mousa; C. Müntz; L. Naumann; J. Otwinowski; Y. C. Pachmayer; M. Palka; Y. Parpottas; V. Pechenov; O. Pechenova; T. Pérez Cavalcanti; J. Pietraszko; W. Przygoda; B. Ramstein; A. Reshetin; M. Roy-Stephan; A. Rustamov; A. Sadovsky; B. Sailer; P. Salabura; A. Schmah; E. Schwab; J. Siebenson; Yu. G. Sobolev; S. Spataro; B. Spruck; H. Ströbele; J. Stroth; C. Sturm; A. Tarantola; K. Teilab; P. Tlusty; M. Traxler; R. Trebacz; H. Tsertos; V. Wagner; M. Weber; C. Wendisch; M. Wisniowski; T. Wojcik; J. Wüstenfeld; S. Yurevich; Y. V. Zanevsky; P. Zumbruch

doi:10.1140/epja/i2013-13034-7

2023 Impact factor 2.6

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2013) 49: 34
https://doi.org/10.1140/epja/i2013-13034-7

Regular Article - Experimental Physics

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

The HADES Collaboration
G. Agakishiev⁸⁹⁸⁶⁴, A. Balanda³⁹⁸⁶⁴, R. Bassini⁹⁹⁸⁶⁴, D. Belver¹⁵⁹⁸⁶⁴, A. V. Belyaev⁶⁹⁸⁶⁴, A. Blanco²⁹⁸⁶⁴, M. Böhmer¹¹⁹⁸⁶⁴, J. L. Boyard¹³⁹⁸⁶⁴, P. Cabanelas¹⁵⁹⁸⁶⁴, E. Castro¹⁵⁹⁸⁶⁴, S. Chernenko⁶⁹⁸⁶⁴, T. Christ¹¹⁹⁸⁶⁴, M. Destefanis⁸⁹⁸⁶⁴, J. Díaz¹⁶⁹⁸⁶⁴, F. Dohrmann⁵⁹⁸⁶⁴, A. Dybczak³⁹⁸⁶⁴, T. Eberl¹¹⁹⁸⁶⁴, E. Epple¹¹⁹⁸⁶⁴, L. Fabbietti¹¹⁹⁸⁶⁴, O. V. Fateev⁶⁹⁸⁶⁴, P. Finocchiaro¹⁹⁸⁶⁴, P. Fonte²⁹⁸⁶⁴, J. Friese¹¹⁹⁸⁶⁴, I. Fröhlich⁷⁹⁸⁶⁴, T. Galatyuk⁷⁹⁸⁶⁴, J. A. Garzón¹⁵⁹⁸⁶⁴, R. Gernhäuser¹¹⁹⁸⁶⁴, A. Gil¹⁶⁹⁸⁶⁴, C. Gilardi⁸⁹⁸⁶⁴, M. Golubeva¹⁰⁹⁸⁶⁴, D. González-Díaz⁴⁹⁸⁶⁴, F. Guber¹⁰⁹⁸⁶⁴, M. Gumberidze¹³⁹⁸⁶⁴, M. Heilmann⁷⁹⁸⁶⁴, T. Heinz⁴⁹⁸⁶⁴, T. Hennino¹³⁹⁸⁶⁴, R. Holzmann⁴⁹⁸⁶⁴, P. Huck¹¹⁹⁸⁶⁴, I. Iori⁹⁹⁸⁶⁴, A. Ivashkin¹⁰⁹⁸⁶⁴, M. Jurkovic¹¹⁹⁸⁶⁴, B. Kämpfer⁵⁹⁸⁶⁴, K. Kanaki⁵⁹⁸⁶⁴, T. Karavicheva¹⁰⁹⁸⁶⁴, D. Kirschner⁸⁹⁸⁶⁴, I. Koenig⁴⁹⁸⁶⁴, W. Koenig⁴⁹⁸⁶⁴, B. W. Kolb⁴⁹⁸⁶⁴, R. Kotte⁵⁹⁸⁶⁴^*, F. Krizek¹⁴⁹⁸⁶⁴, R. Krücken¹¹⁹⁸⁶⁴, W. Kühn⁸⁹⁸⁶⁴, A. Kugler¹⁴⁹⁸⁶⁴, A. Kurepin¹⁰⁹⁸⁶⁴, S. Lang⁴⁹⁸⁶⁴, J. S. Lange⁸⁹⁸⁶⁴, K. Lapidus¹⁰⁹⁸⁶⁴, T. Liu¹³⁹⁸⁶⁴, L. Lopes²⁹⁸⁶⁴, M. Lorenz⁷⁹⁸⁶⁴, L. Maier¹¹⁹⁸⁶⁴, A. Mangiarotti²⁹⁸⁶⁴, J. Markert⁷⁹⁸⁶⁴, V. Metag⁸⁹⁸⁶⁴, B. Michalska³⁹⁸⁶⁴, J. Michel⁷⁹⁸⁶⁴, D. Mishra⁸⁹⁸⁶⁴, E. Morinière¹³⁹⁸⁶⁴, J. Mousa¹²⁹⁸⁶⁴, C. Müntz⁷⁹⁸⁶⁴, L. Naumann⁵⁹⁸⁶⁴, J. Otwinowski³⁹⁸⁶⁴, Y. C. Pachmayer⁷⁹⁸⁶⁴, M. Palka⁴⁹⁸⁶⁴, Y. Parpottas¹²⁹⁸⁶⁴, V. Pechenov⁴⁹⁸⁶⁴, O. Pechenova⁸⁹⁸⁶⁴, T. Pérez Cavalcanti⁸⁹⁸⁶⁴, J. Pietraszko⁴⁹⁸⁶⁴, W. Przygoda³⁹⁸⁶⁴, B. Ramstein¹³⁹⁸⁶⁴, A. Reshetin¹⁰⁹⁸⁶⁴, M. Roy-Stephan¹³⁹⁸⁶⁴, A. Rustamov⁴⁹⁸⁶⁴, A. Sadovsky¹⁰⁹⁸⁶⁴, B. Sailer¹¹⁹⁸⁶⁴, P. Salabura³⁹⁸⁶⁴, A. Schmah¹¹⁹⁸⁶⁴, E. Schwab⁴⁹⁸⁶⁴, J. Siebenson¹¹⁹⁸⁶⁴, Yu. G. Sobolev¹⁴⁹⁸⁶⁴, S. Spataro⁸⁹⁸⁶⁴, B. Spruck⁸⁹⁸⁶⁴, H. Ströbele⁷⁹⁸⁶⁴, J. Stroth⁷⁹⁸⁶⁴^,49864, C. Sturm⁴⁹⁸⁶⁴, A. Tarantola⁷⁹⁸⁶⁴, K. Teilab⁷⁹⁸⁶⁴, P. Tlusty¹⁴⁹⁸⁶⁴, M. Traxler⁴⁹⁸⁶⁴, R. Trebacz³⁹⁸⁶⁴, H. Tsertos¹²⁹⁸⁶⁴, V. Wagner¹⁴⁹⁸⁶⁴, M. Weber¹¹⁹⁸⁶⁴, C. Wendisch⁵⁹⁸⁶⁴, M. Wisniowski³⁹⁸⁶⁴, T. Wojcik³⁹⁸⁶⁴, J. Wüstenfeld⁵⁹⁸⁶⁴, S. Yurevich⁴⁹⁸⁶⁴, Y. V. Zanevsky⁶⁹⁸⁶⁴ and P. Zumbruch⁴⁹⁸⁶⁴

¹⁹⁸⁶⁴ Instituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, 95125, Catania, Italy
²⁹⁸⁶⁴ LIP-Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516, Coimbra, Portugal
³⁹⁸⁶⁴ Smoluchowski Institute of Physics, Jagiellonian University of Cracow, 30-059, Kraków, Poland
⁴⁹⁸⁶⁴ GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
⁵⁹⁸⁶⁴ Institut für Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden, Germany
⁶⁹⁸⁶⁴ Joint Institute of Nuclear Research, 141980, Dubna, Russia
⁷⁹⁸⁶⁴ Institut für Kernphysik, Johann Wolfgang Goethe-Universität, 60438, Frankfurt, Germany
⁸⁹⁸⁶⁴ II.Physikalisches Institut, Justus Liebig Universität Giessen, 35392, Giessen, Germany
⁹⁹⁸⁶⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Milano, 20133, Milano, Italy
¹⁰⁹⁸⁶⁴ Institute for Nuclear Research, Russian Academy of Science, 117312, Moscow, Russia
¹¹⁹⁸⁶⁴ Physik Department E12, Technische Universität München, 85748, München, Germany
¹²⁹⁸⁶⁴ Department of Physics, University of Cyprus, 1678, Nicosia, Cyprus
¹³⁹⁸⁶⁴ Institut de Physique Nucléaire (UMR 8608), CNRS/IN2P3 - Université Paris Sud, F-91406, Orsay Cedex, France
¹⁴⁹⁸⁶⁴ Nuclear Physics Institute, Academy of Sciences of Czech Republic, 25068, Rez, Czech Republic
¹⁵⁹⁸⁶⁴ Departamento de Física de Partículas, Univ. de Santiago de Compostela, 15706, Santiago de Compostela, Spain
¹⁶⁹⁸⁶⁴ Instituto de Física Corpuscular, Universidad de Valencia-CSIC, 46971, Valencia, Spain

^* e-mail: kotte@hzdr.de

Received: 10 December 2012
Accepted: 6 February 2013
Published online: 15 March 2013

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.