Measurement of the $W$-boson production cross-sections in $pp$ collisions at $\sqrt{s}$ = 13 TeV in the forward region

TL;DR

This paper reports a precise measurement of W-boson production cross-sections in proton-proton collisions at 13 TeV using the LHCb detector, focusing on muon decay channels in the forward region.

Contribution

The study provides the most precise measurements to date of W-boson cross-sections in the forward region at 13 TeV, aligning well with advanced theoretical predictions.

Findings

Measured W+ and W- cross-sections with high precision

Results agree with next-to-next-to-leading order QCD predictions

Significantly improved the precision over previous measurements

Abstract

A precision measurement of the $W$-boson production cross-section is performed using the $W \to \mu\nu$ decay channel, based on a sample of proton-proton collision data collected by the LHCb experiment at $\sqrt{s}$ = 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 integrated production cross-sections of $W$ bosons are measured to be $$ \begin{array}{lcl} \sigma_{W^+ \to \mu^+\nu} &=& 1754.2 \pm 1.5 \pm 11.9 \pm 35.1\text{ pb} \\ \sigma_{W^- \to \mu^-\bar{\nu}} &=& 1178.1 \pm 1.3 \pm 9.7 \pm 23.6\text{ pb} \end{array} $$ where uncertainties are statistical, systematic, and due to the luminosity determination, respectively. Results 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.