Forward dihadron correlations in deuteron-gold collisions with a Gaussian approximation of JIMWLK

TL;DR

This paper calculates forward dihadron correlations in deuteron-gold collisions using the Gaussian approximation of JIMWLK, revealing nonlinear effects near the saturation scale and matching experimental features.

Contribution

It introduces a Gaussian approximation for higher point Wilson line correlators in dihadron correlation calculations, including both elastic and inelastic contributions.

Findings

Double parton scattering is included in the model.

The away side peak agrees with experimental data.

Nonlinear effects are visible near the saturation scale.

Abstract

We compute dihadron correlations in forward deuteron-gold or proton-gold collisions. The running coupling BK equation is used to calculate the energy dependence of the dipole cross sections and extended to higher point Wilson line correlators using a factorized Gaussian approximation. Unlike some earlier works we include both the "inelastic" and "elastic" contributions to the dihadron cross section. We show that the double parton scattering contribution is included in our calculation and obtain both an away side peak that roughly agrees with experimental observations and an estimate for the azimuthal angle-independent pedestal. We find that nonlinear effects for momenta close to the saturation scale are clearly visible in the away side peak structure.