Drell-Yan process at forward rapidity at the LHC

TL;DR

This paper investigates the Drell-Yan process at forward rapidity at the LHC, revealing saturation effects and the importance of higher twist contributions at lower invariant masses.

Contribution

It introduces a twist expansion framework within the dipole model to analyze saturation effects in Drell-Yan production at the LHC.

Findings

Significant suppression due to saturation effects compared to collinear factorization.

Leading twist approximation suffices for invariant masses above 6 GeV.

Higher twist contributions become important at lower invariant masses.

Abstract

We analyze the Drell-Yan lepton pair production at forward rapidity at the Large Hadron Collider. Using the dipole framework for the computation of the cross section we find a significant suppression in comparison to the collinear factorization formula due to saturation effects in the dipole cross section. We develop a twist expansion in powers of Q_s^2/M^2 where Q_s is the saturation scale and M the invariant mass of the produced lepton pair. For the nominal LHC energy the leading twist description is sufficient down to masses of 6 GeV. Below that value the higher twist terms give a significant contribution.