Measurement of the Cross Section of W Bosons Produced in pp Collisions at sqrt{s} = 7 TeV With the ATLAS Detector

This dissertation presents a measurement of the inclusive W boson cross section in the muon decay channel, using 7 TeV proton-proton collisions at the Large Hadron Collider. The measurement probes Standard Model QCD predictions at a new regime, at high-Q^2 and low-x in the parton distribution functions. It is also fruitful in understanding the ATLAS detector response to the production of leptons and neutrinos, which are present in many other physics signals. The dataset used corresponds to an integrated luminosity of 33 pb−1, collected by the ATLAS detector during 2010. Lepton quality, kinematic, and isolation requirements, as well as missing energy and transverse mass criteria are adopted to extract the W → μν signal. The major backgrounds come from W → τν, Z → μμ where a muon is lost, and from QCD, particularly from heavy-flavor quark decays. Cross sections and kinematic distributions are compared with Standard Model expectations using next-to-leading-order QCD calculations and several PDF sets.