Applicability of pion-nucleus Drell-Yan data in global analysis of nuclear parton distribution functions

TL;DR

This paper investigates whether pion-nucleus Drell-Yan data can improve the constraints on nuclear parton distribution functions, especially the u/d quark asymmetry, in global analyses.

Contribution

It demonstrates that existing pion-nucleus Drell-Yan data can be incorporated into nPDF analyses without significant theoretical uncertainties, potentially constraining u/d asymmetry.

Findings

NA3, NA10, and E615 data can be used without large theoretical uncertainties.

Pion-nucleus Drell-Yan data may constrain u/d asymmetry in nuclei.

Existing datasets have potential to improve nPDF global fits.

Abstract

Despite the success of modern nuclear parton distribution functions (nPDFs) in describing nuclear hard-process data, they still suffer from large uncertainties. One of the poorly constrained features is the possible asymmetry in nuclear modifications of valence $u$ and $d$ quarks. We study the possibility of using pion-nucleus Drell-Yan dilepton data as a new constraint in the global analysis of nPDFs. We find that the nuclear cross-section ratios from the NA3, NA10 and E615 experiments can be used without imposing significant new theoretical uncertainties and, in particular, that these datasets may have some constraining power on the $u$/$d$ -asymmetry in nuclei.