Precise Predictions forW+3Jet Production at Hadron Colliders

We report on the first next-to-leading order QCD computation of $W+3$-jet production in hadronic collisions including all partonic subprocesses. We compare the results with data from the Tevatron and find excellent agreement. The required one-loop matrix elements are computed using on-shell methods, implemented in a numerical program, BlackHat. We use the SHERPA package to generate the real-emission contributions and to integrate the various contributions over phase space. We use a leading-color (large-$N_c$) approximation for the virtual part, which we confirm in $W+1$, 2-jet production to be valid to within three percent.