Influence of ϕ mesons on negative kaons in Ni+Ni collisions at 1.91A GeV beam energy


Influence of ϕ mesons on negative kaons in Ni+Ni collisions at 1.91A GeV beam energy

Piasecki, K.; Herrmann, N.; Averbeck, R.; Andronic, A.; Barret, V.; Basrak, Z.; Bastid, N.; Benabderrahmane, M. L.; Berger, M.; Buehler, P.; Cargnelli, M.; Čaplar, R.; Crochet, P.; Czerwiakowa, O.; Deppner, I.; Dupieux, P.; Dželalija, M.; Fabbietti, L.; Fodor, Z.; Gasik, P.; Gašparić, I.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kang, T. I.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Kiš, M.; Koczon, P.; Kotte, R.; Lebedev, A.; Leifels, Y.; Le Fèvre, A.; Liu, J. L.; Lopez, X.; Manko, V.; Marton, J.; Matulewicz, T.; Münzer, R.; Petrovici, M.; Rami, F.; Reischl, A.; Reisdorf, W.; Ryu, M. S.; Schmidt, P.; Schüttauf, A.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek-Wilczyńska, K.; Smolyankin, V.; Suzuki, K.; Tymiński, Z.; Wagner, P.; Weber, I.; Widmann, E.; Wiśniewski, K.; Xiao, Z. G.; Yushmanov, I.; Zhang, Y.; Zhilin, A.; Zinyuk, V.; Zmeskal, J.

ϕ and K− mesons from Ni+Ni collisions at the beam energy of 1.91A GeV have been measured by the FOPI spectrometer, with a trigger selecting central and semi-central events amounting to 51% of the total cross section. The phase space distributions, and the total yield of K−, as well as the kinetic energy distribution and the total yield of ϕ mesons are presented. The ϕ\K− ratio is found to be 0.44±0.07(stat)+0.18−0.12(syst), meaning that about 22% of K− mesons originate from the decays of ϕ mesons, occurring mostly in vacuum. The inverse slopes of direct kaons are up to about 15 MeV larger than the ones extracted within the one-source model, signalling that a considerable share of gap between the slopes of K+ and K− could be explained by the contribution of ϕ mesons to negative kaons.

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Publ.-Id: 21383