A measurement of the ratio of the W + 1 jet and Z + 1 jet cross sections using the ATLAS detector at the LHC

The first measurement of the ratio of the W and Z cross sections in association with a single jet, known as the R$_{\rm{Jets}}$ measurement, is presented. The measurement was performed using 33 pb$^{−1}$ of integrated luminosity, recorded during the year 2010 by the ATLAS detector at the LHC. At this time the LHC was operating at a center-of-mass energy of $\sqrt{s}$ = 7 TeV. The measurement is made as a function of the threshold on the jet transverse momentum, from 30 GeV up to a value of 200 GeV. The motivation for this measurement is outlined in terms of providing a stringent test of the Standard Model of particle physics, as well as a model independent tool for searching for new physics. Data driven tools are developed to perform the measurement and their performance is discussed. The result of the measurement is compared with the predictions of Next-to-Leading order perturbative QCD and found to be in good agreement over the entire range of transverse momenta considered.