This thesis presents a measurement of W boson production in association with jets using 20.2 fb−1 of data of proton-proton collisions at the ATLAS detector. The collisions were at a center of mass energy of √s = 8 TeV, and all the data were collected in 2012. Differential cross sections and the ratio of W+ to W− cross sections are shown for W → eν decays in the presence of jets with transverse momentum pT > 30 and jet rapidity |η| < 4.4. The observables shown have proven difficult to model in the past, including the transverse momentum of the W boson, and the scalar sum of the transverse momenta of all hard objects HT. These observables test the theoretical understanding of perturbative QCD. The data are compared to leading order, next-to leading order, and next-to-next-to leading order predictions in QCD. In the W+/W− ratio many systematic uncertainties cancel out, improving the precision of the measurement by up to a factor of nine.
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