A measurement of the ratio of the production cross sections for W and Z bosons in association with jets with the ATLAS detector

The ratio of the production cross sections for W and Z bosons in association with jets has been measured in proton–proton collisions at s=7TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is based on the entire 2011 dataset, corresponding to an integrated luminosity of 4.6fb-1 . Inclusive and differential cross-section ratios for massive vector bosons decaying to electrons and muons are measured in association with jets with transverse momentum pT>30GeV and jet rapidity |y|<4.4 . The measurements are compared to next-to-leading-order perturbative QCD calculations and to predictions from different Monte Carlo generators implementing leading-order matrix elements supplemented by parton showers.