  The unique forward LHCb acceptance opens the possibility for performing
precision Standard Model (SM) processes in a kinematical regime beyond the
reach of both ATLAS and CMS experiments. In this article we discuss the
feasibility of performing $W^{\pm}j$ measurements with 14 TeV LHCb data, and
find that the leptonic asymmetry at high pseudorapidity, with appropriate cuts
on the associated jet, can provide a factor of three reduction on the $d$ quark
PDF uncertainty in a region of Bjorken $x > 0.5$.
