Vector Boson + Jets with BlackHat and SHERPA

We review recent NLO QCD results for W, Z+3-jet production at hadron colliders, computed using BlackHat and SHERPA. We also include some new results for Z+3-jet production at the LHC at 7 TeV. We report new progress towards the NLO cross section for W+4-jet production. In particular, we show that the virtual matrix elements produced by BlackHat are numerically stable. We also show that with an improved integrator and tree-level matrix elements from BlackHat, SHERPA produces well-behaved real-emission contributions. As an illustration, we present the real-emission contributions - including dipole-subtraction terms - to the pT distribution of the fourth jet, for a single subprocess with the maximum number of gluons.