Directed flow in Au+Au, Xe+CsI and Ni+Ni collisions and the nuclear equation of state


Directed flow in Au+Au, Xe+CsI and Ni+Ni collisions and the nuclear equation of state

Andronic, A.; Reisdorf, W.; Herrmann, N.; Crochet, P.; Barret, V.; Basrak, Z.; Bastid, N.; Berek, G.; Caplar, R.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Finck, C.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Koczon, P.; Korolija, M.; Kotte, R.; Kress, T.; Lebedev, A.; Lee, K. S.; Leifels, Y.; Lopez, X.; Merschmeyer, M.; Neubert, W.; Pelte, D.; Petrovici, M.; Rami, F.; de Schauenburg, B.; Schuettauf, A.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek-Wilczynska, K.; Smolyankin, V.; Stockmeier, M.; Stoicea, G.; Tyminski, Z.; Wagner, P.; Wisniewski, K.; Wohlfarth, D.; Yushmanov, I.; Zhilin, A.

We present new experimental data on directed flow in collisions of Au+Au, Xe+CsI and Ni+Ni at incident energies from 90 to 400 A MeV. We study the centrality and system dependence of integral and differential directed flow for particles selected according to charge. All the features of the experimental data are compared with Isospin Quantum Molecular Dymnamics (IQMD) model calculations in an attempt to extract information about the nuclear matter equation of state (EoS). We show that the combination of rapidity and transverse momentum analysis of directed flow allows to disentangle various parametrizations in the model. At 400 A MeV, a soft EoS with momentum dependent interactions is best suited to explain the experimental data in Au+Au and Xe+CsI, but in case of Ni+Ni the model underpredicts flow for any EoS. At 90 A MeV beam energy, none of the IQMD parametrizations studied is able to consistently explain the experimental data.

  • Phys. Rev. C 67 (2003) 034907

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