Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC

摘要

We present the first results of meson production in the K^+K^- decay channelfrom Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity bythe PHENIX detector at RHIC. Precision resonance centroid and width values areextracted as a function of collision centrality. No significant variation fromthe PDG accepted values is observed. The transverse mass spectra are fittedwith a linear exponential function for which the derived inverse slopeparameter is seen to be constant as a function of centrality. These data arealso fitted by a hydrodynamic model with the result that the freeze-outtemperature and the expansion velocity values are consistent with the valuespreviously derived from fitting single hadron inclusive data. As a function oftransverse momentum the collisions scaled peripheral.to.central yield ratio RCPfor the is comparable to that of pions rather than that of protons. This resultlends support to theoretical models which distinguish between baryons andmesons instead of particle mass for explaining the anomalous proton yield.