Measurement of the W±Z boson pair-production cross section in pp collisions at s=13 TeV with the ATLAS detector

Abstract

The production of W±Z events in proton–proton collisions at a centre-of-mass energy of 13 TeV is measured with the ATLAS detector at the LHC. The collected data correspond to an integrated luminosity of 3.2 fb−1. The W±Z candidates are reconstructed using leptonic decays of the gauge bosons into electrons or muons. The measured inclusive cross section in the detector fiducial region for leptonic decay modes is σW fid.=63.2±3.2(stat.)±2.6(sys.)±1.5(lumi.) fb. In comparison, the next-to-leading-order Standard Model prediction is 53.4−2.8 +3.6 fb. The extrapolation of the measurement from the fiducial to the total phase space yields σW tot.=50.6±2.6(stat.)±2.0(sys.)±0.9(th.)±1.2(lumi.) pb, in agreement with a recent next-to-next-to-leading-order calculation of 48.2−1.0 +1.1 pb. The cross section as a function of jet multiplicity is also measured, together with the charge-dependent W+Z and W−Z cross sections and their ratio.