Measurement of the W boson mass

TL;DR

This paper reports a measurement of the W boson mass using proton-proton collision data at 13 TeV from the LHCb experiment, employing a simultaneous fit of muon and Z boson decay distributions, resulting in a value consistent with the Standard Model and previous measurements.

Contribution

First measurement of the W boson mass at 13 TeV using LHCb data with a novel simultaneous fit method of muon and Z decay distributions.

Findings

Measured W boson mass: 80354 ± 23 (stat) ± 10 (exp) ± 17 (theory) ± 9 (PDF) MeV.

Result agrees with the global electroweak fit and previous measurements.

Used three recent global PDF sets for the analysis.

Abstract

The $W$ boson mass is measured using proton-proton collision data at $\sqrt{s}=13$ TeV corresponding to an integrated luminosity of 1.7 fb$^{-1}$ recorded during 2016 by the LHCb experiment. With a simultaneous fit of the muon $q/p_T$ distribution of a sample of $W \to \mu\nu$ decays and the $\phi^*$ distribution of a sample of $Z\to\mu\mu$ decays the $W$ boson mass is determined to be \begin{equation*} m_{W} = 80354 \pm 23_{\rm stat} \pm 10_{\rm exp} \pm 17_{\rm theory} \pm 9_{\rm PDF}~\mathrm{MeV}, \end{equation*} where uncertainties correspond to contributions from statistical, experimental systematic, theoretical and parton distribution function sources. This is an average of results based on three recent global parton distribution function sets. The measurement agrees well with the prediction of the global electroweak fit and with previous measurements.