J/ψ production in Au-Au collisions at √s_NN=200 GeV

Abstract

First results on charm quarkonia production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/ψ's measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au-Au reactions at √s_NN=200 GeV is analyzed as a function of collision centrality. For this analysis we have studied 49.3×10⁶ minimum bias Au-Au reactions. We present the J/ψ invariant yield dN/dy for peripheral and midcentral reactions. For the most central collisions where we observe no signal above background, we quote 90% confidence level upper limits. We compare these results with our J/ψ measurement from proton-proton reactions at the same energy. We find that our measurements are not consistent with models that predict strong enhancement relative to binary collision scaling.