Contribution Invited plenary
The Asymmetry in the antimatter of the proton
Protons are understood as states of quarks and gluons bound by the strong force, but the dynamics that form a proton from quarks and gluons is poorly understood. Contrary to naive assumptions, there is an asymmetry between d and u anti-quarks. This asymmetry cannot arise from pQCD and demonstrates a fundamental anti-quark component in the proton. SeaQuest has measured the deuterium to hydrogen Drell-Yan cross section ratio and extracted anti-d/anti-u as a function of quark momentum fraction x.