Charged particle to photon ratio in heavy-ion collisions at RHIC: a different point of view

Abstract

We report an alternative explanation of the variation of charged particle to photon ratio in Cu+Cu collisions and Au+Au collisions from 1.4 ± 0.1 to 1.262.4 GeV and 200 GeV respectively in STAR experiment at RHIC. Based on the theoretical predictions and experimental results we argue that the additional contribution of direct photons at √ s NN = 200 GeV in both Cu+Cu and Au+Au collisions are improving the ratio N ch Nγ to 1.2 ± 0.1 from 1.4 ± 0.1.