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

Abstract

Measurements of the W± → ±ν and Z → +− production cross sections (where ± =e±, µ±) in proton–proton collisions at √s = 13 TeV are presented using data recorded by the ATLAS experiment at the Large Hadron Collider, corresponding to a total integrated luminosity of 81 pb−1. The total inclusive W± -boson production cross sections times the singlelepton-flavour branching ratios are σ tot W+ = 11.83 ± 0.02 (stat) ± 0.32 (sys) ± 0.25 (lumi) nb and σ tot W− = 8.79 ± 0.02 (stat) ± 0.24 (sys) ± 0.18 (lumi) nb for W+ and W−, respectively. The total inclusive Z-boson production cross section times leptonic branching ratio, within the invariant mass window 66 < m`` < 116 GeV, is σ tot Z= 1.981 ± 0.007 (stat) ± 0.038 (sys) ±0.042 (lumi) nb. The W+, W−, and Z-boson production cross sections and cross-section ratios within a fiducial region defined by the detector acceptance are also measured. The cross section ratios benefit from significant cancellation of experimental uncertainties, resulting in σ fid W+ /σfid W− = 1.295±0.003 (stat)±0.010 (sys) and σ fid W± /σfidZ= 10.31±0.04 (stat)±0.20 (sys). Theoretical predictions, based on calculations accurate to next-to-next-to-leading order for quantum chromodynamics and to next-to-leading order for electroweak processes and which employ different parton distribution function sets, are compared to these measurements.