Direct photon production in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV at STAR

Abstract

We present the direct photon production for $1<p_T<10$ GeV/$c$ derived from continuum in the dielectron invariant mass region $0.1<M_{ee}<0.3$ GeV/$c^2$ from one billion $\sqrt{s_{NN}}=200$ GeV Au+Au events taken in year 2010 and 2011. A clear excess in the invariant yield compared to the number of binary collision scaled $p+p$ reference is observed in the \pt~range 1-4 GeV/$c$. Model calculations with contributions from thermal radiation and initial hard parton scattering are consistent within uncertainties with the direct photon invariant yield.

Comments: 4 pages, 5 figures, QM2014 proceedings