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 mea- sured in proton–proton collisions at √s = 7 TeV with the ATLAS experiment at the Large Hadron Collider. The mea- surement is based on the entire 2011 dataset, correspond- ing to an integrated luminosity of 4.6 fb−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 > 30 GeV and jet rapidity |y| < 4.4. The measurements are compared to next- to-leading-order perturbative QCD calculations and to pre- dictions from different Monte Carlo generators implement- ing leading-order matrix elements supplemented by parton showers.