Nuclear effects in the proton-deuteron Drell-Yan process

TL;DR

This paper calculates nuclear effects on the proton-deuteron Drell-Yan process, including smearing and off-shell corrections, to improve the extraction of the dbar/ubar ratio in the proton sea at various x values.

Contribution

It introduces a comprehensive analysis of nuclear corrections, especially off-shell effects, in the Drell-Yan process for the first time.

Findings

Off-shell nucleon corrections are significant at intermediate and large x_N.

Nuclear smearing effects are important at large x_N.

Results are relevant for current and future experiments at Fermilab and J-PARC.

Abstract

We compute the nuclear corrections to the proton-deuteron Drell-Yan cross section for inclusive dilepton production, which, when combined with the proton-proton cross section, is used to determine the flavor asymmetry in the proton sea, dbar - ubar. In addition to nuclear smearing corrections that are known to be important at large values of the nucleon's parton momentum fraction x_N, we also consider dynamical off-shell nucleon corrections associated with the modifications of the bound nucleon structure inside the deuteron, which we find to be significant at intermediate and large x_N values. We also provide estimates of the nuclear corrections at kinematics corresponding to existing and planned Drell-Yan experiments at Fermilab and J-PARC which aim to determine the dbar/ubar ratio for x < 0.6.