Measurement of the W -boson production cross sections in p p collisions at s = 13 TeV in the forward region

A precision measurement of the W -boson production cross section is performed using the W → μ ν decay channel, based on a sample of proton-proton collision data collected by the LHCb experiment at s = 13 TeV and corresponding to an integrated luminosity of 5.1 fb − 1 . The cross section is measured for muons with transverse momentum between 25 and 55 GeV and pseudorapidity between 2.0 and 4.5. The total production cross sections of W bosons are measured to be σ W + → μ + ν = 1754.2 ± 1.5 ± 11.8 ± 35.1 pb σ W − → μ − ν ¯ = 1178.1 ± 1.3 ± 9.7 ± 23.6 pb where uncertainties are statistical, systematic, and due to the luminosity determination, respectively. Differential distributions d σ W ± → μ ± ν / d η μ ± are also presented. The total and differential cross sections are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. This measurement is significantly more precise than previous results in this kinematic regime.