Studies of vector boson + jet production with ATLAS

The production of jets in association with a W or Z boson in proton-proton collisions at 7 TeV is an important process to understand in QCD. The cross section, differential in several kinematics variables, has been measured up to high jet multiplicities and compared to new higher-order QCD calculations. The ratio of (Z + a single jet)/(W + a single jet) can provide a very precise test of QCD and has also been measured. In addition, the cross sections for vector bosons produced with bottom jets, Z+b-jet and W+b-jet, have been measured and compared to NLO QCD calculations. Overall, the cross sections demonstrate the need for the inclusion of higher-multiplicity matrix elements in the calculations, even in cases where a parton shower simulation is present.