Systematic studies of the centrality and √s_NN dependence of the dE_T/dη and dN_ch/dη in heavy ion collisions at midrapidity

Abstract

The PHENIX experiment at the relativistic heavy ion collider (RHIC) has measured transverse energy and charged particle multiplicity at midrapidity in Au+Au collisions at center-of-mass energies √s_NN=19.6,130, and 200 GeV as a function of centrality. The presented results are compared to measurements from other RHIC experiments and experiments at lower energies. The √s_NN dependence of dE_T/dη and dN_ch/dη per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of dE_T/dη and dN_ch/dη is similar at all measured incident energies. At RHIC energies, the ratio of transverse energy per charged particle was found to be independent of centrality and growing slowly with √s_NN. A survey of comparisons between the data and available theoretical models is also presented.