Measurement of p+d/p+p Cross-Section Ratio of Drell-Yan Process at FNAL-SeaQuest

The partonic structure of the proton is of great interest in hadron physics. Particularly the distribution of anti-quarks has gained a lot of attention due to its unique sensitivity to the dynamics of the strong force (i.e. QCD). A large flavor asymmetry of the unpolarized distributions of light anti-quarks (i.e. anti-d(x) / anti-u(x)) was observed by several experiments through the deep-inelastic muon scattering and the Drell-Yan process. The mechanism of the asymmetry has been studied via various theoretical models. SeaQuest at Fermilab is a fixed-target experiment to measure the Drell-Yan process in proton+proton and proton+deuteron scattering, using the 120-GeV proton beam and targets of LH2, LD2, C, Fe and W. SeaQuest's primary goal is to precisely measure the anti-quark flavor asymmetry, anti-d(x)/anti-u(x), at large x through the ratio of p+d and p+p cross sections. The latest results from SeaQuest using an updated and higher precision measurement on anti-d(x)/anti-u(x) will be presented in the context of various theoretical models.