Twist expansion of forward Drell-Yan process

TL;DR

This paper develops a twist expansion framework for the forward Drell-Yan process at high energies, utilizing the GBW saturation model, and predicts potential experimental signatures such as the breaking of the Lam-Tung relation at twist 4.

Contribution

It introduces a twist expansion approach for the forward Drell-Yan process incorporating saturation effects and predicts observable higher-twist phenomena at LHC energies.

Findings

Saturation scale acts as the hadronic scale in the OPE.

Explicit predictions for LHC experiments are provided.

The Lam-Tung relation is broken at twist 4, indicating higher-twist effects.

Abstract

We present a twist expansion of differential cross-sections of the forward Drell-Yan process at the high energies. The expansion of all invariant form-factors is performed assuming GBW saturation model and the saturation scale plays the role of the hadronic scale of OPE. Some expilicit predictions for LHC experiments are given. It is shown also how the Lam-Tung relation is broken at twist 4 what provides a sensitive probe for searching of higher twists.