# Nuclear modification of forward Drell-Yan production at the LHC

## TL;DR

This paper investigates how nuclear effects modify forward Drell-Yan production at the LHC, using the color dipole approach and optical Glauber model to compare with J/psi production, aiming to distinguish initial and final state effects.

## Contribution

It introduces a method to compute nuclear modification factors for Drell-Yan and J/psi production using the color dipole approach and Glauber model, providing a new observable for experimental analysis.

## Key findings

- Predicted nuclear modification ratios for Drell-Yan and J/psi production.
- Proposed the ratio as a tool to distinguish initial from final state effects.
- Provided theoretical predictions relevant for upcoming LHC measurements.

## Abstract

Forward Drell-Yan production at high energy can provide important constraints on gluon densities at small $x$, in the saturation regime. In this work we focus on the nuclear modification of this process, which could be measured at the LHC in the near future. For this we employ the color dipole approach, using the optical Glauber model to relate the dipole cross section of a nucleus to the one of a proton. Combining these results with our earlier results for forward $J/\psi$ production, we compute the ratio of the nuclear modification factors of these two processes. This observable was recently suggested as a way to distinguish between initial and final state effects in forward particle production.