Large-x d/u Ratio in W-boson Production

Recent analysis of proton and deuteron deep-inelastic scattering data have suggested that the extracted d/u quark distribution ratio at large x may be significantly larger than previously believed, if the data are corrected for nuclear binding effects in the deuteron. We examine the sensitivity to the large-x d/u ratio of lepton asymmetries from W-boson production in p-pbar and p-p collisions at large rapidity, which do not suffer from nuclear contamination.