A Measurement of the Ratio of the W + 1 Jet to Z + 1 Jet Cross Sections with ATLAS

Abstract: The measurement of hadronic activity recoiling against W and Z vector bosons provides an important test of perturbative QCD, as well as a method of searching for new physics in a model independent fashion. We present a study of the cross-section ratio for the production of W and Z gauge bosons in association with exactly one jet Rjet = {\sigma}(W + 1jet)/{\sigma}(Z + 1jet), in pp collisions at \surds = 7 TeV. The study is performed in the electron and muon channels with data collected with the ATLAS detector at the LHC. The ratio Rjet is studied as a function of the cumulative transverse momentum distribution of the jet. This result can be compared to NLO pQCD calculations and the prediction from LO matrix element + parton shower generators.