Extraction of Spin-Averaged Light Quark Sea Asymmetry using SeaQuest Data*

We present a new global QCD analysis of inclusive unpolarized data, using a Monte Carlo approach to extract the spin-averaged PDFs. We focus on the light quark sea asymmetry and include new Drell-Yan data from the SeaQuest experiment at Fermilab and $W$-lepton production data from the STAR collaboration at RHIC. We find that the SeaQuest experiment provides strong constraints on the asymmetry, and confirms that it must remain positive up to parton momentum fractions of $x=0.4$, as predicted by models in which the asymmetry arises from chiral symmetry breaking in QCD.