The extraction of the nuclear sea-quark distribution and energy loss effect in a Drell–Yan experiment

A next-to-leading order and a leading order analysis are performed of the differential cross section ratios from the Drell–Yan process. It is found that the effect of next-to-leading order corrections on the differential cross section ratios as a function of the quark momentum fraction in the proton beam and the target nuclei for the current Fermilab and future lower proton energy beam can be considered negligible. The nuclear Drell–Yan reaction is an ideal tool to study the energy loss of fast quarks moving through cold nuclei. In a leading order analysis, the theoretical results with the quark energy loss are in good agreement with the Fermilab E866 experimental data on the Drell–Yan differential cross section ratios as a function of the momentum fraction of the target parton. It is shown that the quark energy loss effect has a significant impact on the Drell–Yan differential cross section ratios. Therefore, it is important to understand the energy loss effects for determining nuclear sea-quark distributions from future nuclear Drell–Yan experiments at the lower energy proton beams bombarding nuclei.