Pion-nucleus Drell-Yan data as a novel constraint for nuclear PDFs

TL;DR

This paper investigates the potential of pion-nucleus Drell-Yan data to serve as a new constraint in global nuclear PDF analyses, showing compatibility with existing data and exploring flavor asymmetry constraints.

Contribution

It demonstrates that pion-nucleus Drell-Yan data can be integrated into global nPDF fits without significant uncertainties and explores their impact on flavor asymmetry in nuclear modifications.

Findings

NA3, NA10, and E615 data are compatible with existing nPDFs.

Pion-nucleus Drell-Yan data can be included without adding significant uncertainties.

Predictions for pion charge-difference ratio could further constrain flavor asymmetry.

Abstract

We have studied the prospects of using the Drell-Yan dilepton process in pion-nucleus collisions as a novel input in the global analysis of nuclear parton distribution functions (nPDFs). In a NLO QCD framework, we find the measured nuclear cross-section ratios from the NA3, NA10 and E615 experiments to be largely insensitive to the pion parton distributions and also compatible with the EPS09 and nCTEQ15 nPDFs. These data sets can thus be, and in EPPS16 have been, included in global nPDF analyses without introducing significant new theoretical uncertainties or tension with the other data. In particular, we explore the constraining power of these data sets on the possible flavour asymmetry in the valence-quark nuclear modifications. Moreover, using the COMPASS kinematics we present predictions for pion charge-difference ratio, a new measurable which could help to further constrain this asymmetry.