High-precision QCD at hadron colliders: Electroweak gauge boson rapidity distributions at next-to-next-to leading order

We compute the rapidity distributions of W and Z bosons produced at the Fermilab Tevatron and the CERN LHC through next-to-next-to leading order in QCD. Our results demonstrate remarkable stability with respect to variations of the factorization and renormalization scales for all values of rapidity accessible in current and future experiments. These processes are therefore ``gold-plated'': current theoretical knowledge yields QCD predictions accurate to better than 1%. These results strengthen the proposal to use W and Z production to determine parton-parton luminosities and constrain parton distribution functions at the LHC. For example, LHC data should easily be able to distinguish the central parton distribution fit obtained by MRST from that obtained by Alekhin.