Elliptic flow of charged and strange hadrons in PbAu collisions at 158 AGeV/c measured in CERES experiment

¹ University of Belgrade and Vinča Institute of Nuclear Sciences, Belgrade, Serbia
² Ruprecht Karls Universität, Heidelberg, Germany

^a e-mail: Jovan.Milosevic@cern.ch

Published online: 29 April 2014

Abstract

Differential elliptic flow of υ₂(p_T) for π⁻, K_s⁰, p and Λ is measured at centerof-mass energy of √s_NN=17.3 GeV near the mid-rapidity region in rather central PbAu collisions collected by the CERES/NA45 experiment at CERN. The proton υ₂(p_T) is extracted from π⁺ sample and particle ratios measured by NA49 experiment adapted to CERES conditions. The proton υ₂(p_T) data show a downward swing towards low p_T with excursions into negative υ₂ values which was not observed earlier. The results are compared with corresponding measurements performed at NA49 and STAR experiments as well as with theoretical predictions from ideal relativistic hydrodynamics. The obtained results for baryons are below hydrodynamic predictions even at the kinetic freeze-out temperature of T_f=160 MeV which needs introducing of a viscous hydrodynamics at the late hadronic phase.