Helicity parton distributions from spin asymmetries in W -boson production at RHIC

We present a next-to-leading-order QCD calculation of the cross section and longitudinal spin asymmetry in single-inclusive charged-lepton production, pp→^±X, at the Relativistic Heavy Ion Collider, where the lepton is produced in the decay of an electroweak gauge boson. Our calculation is presented in terms of a multipurpose Monte Carlo integration program that may be readily used to include experimental spin-asymmetry data in a global analysis of helicity parton densities. We perform a toy global analysis, studying the impact of anticipated Relativistic Heavy Ion Collider data on our knowledge about the polarized antiquark distributions.