Quantifying Photoproduction Corrections to J/ψMeasurements in Au+Au and Cu+Cu Collisions at $\sqrt{s_{NN}}=200$ GeV

Abstract

The contribution of J/ψproduction from coherent and incoherent photon-induced production is calculated in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV. The yield and nuclear modification factors ($R_{AA}$) contributed by photoproduction are presented as functions of transverse momentum ($p_T$) and centrality at both mid- and forward rapidity. The $R_{AA}$ of J/ψfrom photoproduction is found to be as high as 0.6 in the lowest $p_T$ bin ($0<p_T<1$ GeV/$c$) at mid-rapidity in 60-92\% Au+Au collisions. The $R_{AA}$ measured in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV are corrected by subtracting the calculated photoproduction contribution.

arXiv comment7 pages, 7 figures