Looking for the gluonic EMC effect in associated J/ψ+γ production

Abstract

We study the associated production of J/ψ+γ in fixed-target experiments with nuclear targets as well as at the relativistic heavy-ion collider (RHIC). We find that this process affords a very clean probe of ρ_g, the ratio of gluon density in a heavy nucleus to that of proton. The combined x range thus available can be used todiscriminate between the predictions of different models of the EMC effect for ρ_g.