Charge asymmetry of weak boson production at the LHC and the charm content of the proton

We investigate the production of the weak bosons W⁺, W ^- and Z at the LHC as a function of their rapidity, reconstructed experimentally from their leptonic decay. We show that the measurements provide a powerful tool for constraining the parton distribution functions, as was already the case for the lower energy pp̄ collider data. We study the charge asymmetry determining the u and d distribution functions using the reconstructed W⁺, W^- rapidities. We also show how the ratio of the W and Z boson rapidity distributions directly probes the charm quark distribution function of the proton.