Measurement of the cross-section for W production in association with b-jets in proton-proton collisions at √=7 TeV at the LHC using the ATLAS detector

This dissertation presents a measurement of the W+b-jets (pp → W + b( ̄b) + X) production cross-section in proton–proton collisions at a center-of-mass energy of 7 TeV at the LHC. The results are based on data corresponding to an integrated luminosity of 4.6 fb−1, collected with the ATLAS detector. The measurement probes the QCD sector of the Standard Model at high energy, in a region where b-quark mass and double parton scattering play an important role. In addition, the measurement is relevant for searches for physics beyond the Standard Model in final states with a W boson and b-jets. The measurement relies on the leptonic decay modes of the W, and on the iden- tification of b-jets. The backgrounds to the W+b-jets process are estimated using Monte Carlo simulation and data-driven techniques. Cross-sections, corrected for all known detector effects and quoted in a limited kinematic range, are presented as a function of jet multiplicity and of the transverse momentum of the leading b-jet for both the muon and electron decay modes of the W boson.