$K^+$ production in the reaction $^{58}$Ni + $^{58}$Ni at incident energies from 1 to 2 A GeV

D. Best , N. Herrmann , B. Hong , M. Kirejczyk , J. Ritman , K. Wisniewski , A. Zhilin , A. Gobbi , K.D. Hildenbrand , Y. Leifels , C. Pinkenburg , W. Reisdorf , D. Schull , U. Sodan , G.S. Wang , T. Wienold , J-P. Alard (1) , V. Amouroux (1) , N. Bastid (1) , I. Belyaev , G. Berek , J. Biegansky , R. Cherbachev , J.P. Coffin (2) , P. Crochet (2) , P. Dupieux (1) , Z. Fodor , A. Genoux-Lubain (1) , G. Goebels , G. Guillaume (2) , E. Hafele , F. Jundt (2) , J. Kecskemeti , Y. Korchagin , R. Kotte , C. Kuhn (2) , A. A. Lebedev , I. Legrand , C. Maazouzi (2) , V. Manko , J. Mosner , S. Mohren , D. Moisa , W. Neubert , D. Pelte , M. Petrovici , P. Pras , F. Rami (2) , C. Roy (2) , Z. Seres , B. Sikora , V. Simion , K. Siwek-Wilczynska , V. Smolyankin , A. Somov , L. Tizniti , M. Trzaska , M.A. Vasilev , P. Wagner (2) , D. Wohlfarth , I. Yushmanov

1 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
2 IReS - Institut de Recherches Subatomiques

Semi-inclusive triple differential multiplicity distributions of positively charged kaons have been measured over a wide range in rapidity and transverse mass for central collisions of $^{58}$Ni with $^{58}$Ni nuclei. The transverse mass ($m_t$) spectra have been studied as a function of rapidity at a beam energy 1.93 AGeV. The $m_t$ distributions of K^+ mesons are well described by a single Boltzmann-type function. The spectral slopes are similar to that of the protons indicating that rescattering plays a significant role in the propagation of the kaon. Multiplicity densities have been obtained as a function of rapidity by extrapolating the Boltzmann-type fits to the measured distributions over the remaining phase space. The total K^+ meson yield has been determined at beam energies of 1.06, 1.45, and 1.93 AGeV, and is presented in comparison to existing data. The low total yield indicates that the K^+ meson can not be explained within a hadro-chemical equilibrium scenario, therefore indicating that the yield does remain sensitive to effects related to its production processes such as the equation of state of nuclear matter and/or modifications to the K^+ dispersion relation.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

D. Best, N. Herrmann, B. Hong, M. Kirejczyk, J. Ritman, et al.. $K^+$ production in the reaction $^{58}$Ni + $^{58}$Ni at incident energies from 1 to 2 A GeV. Nuclear Physics A, 1997, 625, pp.307-324. ⟨in2p3-00003629⟩