Standard Model measurements with the ATLAS detector

Abstract

Various Standard Model measurements have been performed in proton-proton collisions at a centre-of-mass energy of √ s = 7 and 8 TeV using the ATLAS detector at the Large Hadron Collider. A review of a selection of the latest results of electroweak measurements, W/Z production in association with jets, jet physics and soft QCD is given. Measurements are in general found to be well described by the Standard Model predic- tions. been performed in proton-proton collisions at a centre-of-mass energy of √ s = 7 and 8 TeV using the ATLAS detector (1) at the LHC. These allow for precision tests of the electroweak dynamics of the Standard Model, but also challenge next-to-next-to-leading-order predictions. Differences between measurements and Standard Model predictions could prove evidence for new phenomena. Recent Quantum Chromo Dynamics (QCD) results highlight the importance of precision QCD measurements for improving state-of-the-art theoretical tools and searching for new physics. A selection of the latest results of electroweak measurements, W/Z production in association with jets, jet physics and soft QCD is reported. These consist of the measurement of the WW cross section, first evidence of the electroweak production of W ± W ± jj , and electroweak Zj jproduction. Measurements are in general found to be well described by the Standard Model predictions. Measurements of differential produc- tion cross sections of a Z boson in association with b-jets, the production cross section of the W boson in association with jets as well as the ratio of the production cross sections for W and Z bosons in association with jets are presented. The measurements are compared to next-to-leading-order pertur- bative QCD calculations and to predictions from different Monte Carlo (MC) generators implement- ing leading-order matrix elements supplemented by parton showers. Various inclusive, differential or double differential jet measurements are presented. The dominant experimental uncertainty on these measurements comes from the jet energy scale. Next-to-leading order QCD calculations corrected to account for non-perturbative effects are compared to the measurements. A good agreement between the data and the theoretical predictions based on most of the global parton distribution functions is found over the full kinematic range, covering almost seven orders of magnitude in the measured cross-section values. A measurement of charged-particle distributions sensitive to the properties of