The leptonic $W^{\pm}$ boson asymmetry in association with jets at LHCb, and PDF constraints at large-$x$

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 $x > 0.5$.
Comment: 6 pages + references, 5 figures, matches PRD version. Some extra detail and discussion in the statistical analysis section