Photons from the Color Glass Condensate in p+A collisions

Abstract

We report on a first NLO computation of photon production in p+A collisions at collider energies within the Color Glass Condensate framework, significantly extending previous LO results. At central rapidites, our result is the dominant contribution and probes multi-gluon correlators in nuclei. At high photon momenta, the result is directly sensitive to the nuclear gluon distribution. The NLO result contains two classes of processes, the annihilation process and the process with qq̄ pair together with a photon in the final state. Using the McLerran-Venugopalan model, we show full numerical results for the photon spectrum coming from the annihilation process.