K0 and Λ production in Ni+Ni collisions near threshold

K0 and Λ production in Ni+Ni collisions near threshold

Merschmeyer, M.; Lopez, X.; Bastid, N.; Crochet, P.; Herrmann, N.; Andronic, A.; Barret, V.; Basrak, Z.; Benabderrahmane, M. L.; Caplar, R.; Cordier, E.; Dupieux, P.; Dzelalija, M.; Fodor, Z.; Gasparic, I.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kang, T. I.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Kis, M.; Matulewicz, T.; Koczon, P.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Mangiarotti, A.; Pelte, D.; Petrovici, M.; Rami, F.; Reisdorf, W.; Ryu, M. S.; Schüttauf, A.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek-Wilczynska, K.; Smolyankin, V.; Stoicea, G.; Tyminski, Z.; Wisniewski, K.; Xiao, Z.; Xu, H. S.; Yushmanov, I.; Zhang, X. Y.; Zhilin, A.

New results concerning the production of neutral strange particles, K0 and Λ in Ni+Ni collisions at 1.93 AGeV, measured with the FOPI detector at GSI Darmstadt, are presented. Rapidity density distributions and Boltzmann slope parameter distributions are measured in nearly the full phase space of the reaction. The observables are compared to existing K+ and proton data. While the K0 data agree with previously reported K+ measurements, the Λ distributions show a different behavior relative to that of protons. The strangeness balance and the production yield per participating nucleon as a function of the centrality of the reaction are discussed, for the first time at SIS energies.

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