Direct photons at forward rapidities in high-energy pp collisions

TL;DR

This paper studies direct photon production at forward rapidities in high-energy proton-proton collisions, highlighting the potential for new measurements and the sensitivity to gluon saturation effects using various color-dipole models.

Contribution

It introduces a detailed analysis of direct photon production at forward rapidities across different energies using color-dipole models, emphasizing the sensitivity to gluon saturation and the anomalous dimension.

Findings

Photon production peaks at forward rapidities due to abelian dynamics.

Measurement opportunities are enhanced at forward rapidities where background is suppressed.

Photon production is sensitive to gluon saturation effects and the anomalous dimension.

Abstract

We investigate direct photon production in pp collisions at the energies of RHIC, CDF and LHC, at different rapidities employing various color-dipole models. The cross section peaks at forward rapidities due to the abelian dynamics of photon radiation. This opens new opportunities for measurement of direct photons at forward rapidities, where the background from radiative hadronic decays is strongly suppressed. Our model calculations show that photon production is sensitive to the gluon saturation effects, and strongly depends on the value of the anomalous dimension.