Measurement of the W boson mass

Abstract

The W boson mass is measured using proton-proton collision data at $$ \sqrt{s} $$ 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/pT distribution of a sample of W → μν decays and the ϕ* distribution of a sample of Z → μμ decays the W boson mass is determined to be$$ {m}_w=80354\pm {23}_{\mathrm{stat}}\pm {10}_{\mathrm{exp}}\pm {17}_{\mathrm{theory}}\pm {9}_{\mathrm{PDF}}\mathrm{MeV}, $$ m w = 80354 ± 23 stat ± 10 exp ± 17 theory ± 9 PDF MeV , 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.

Oblique Lessons from the $W$ Mass Measurement at CDF II

“…They report M W,CDF II = 80.4335 ± 0.0094 GeV, (1) which, without averaging with other experimental results, shows a 7σ deviation from the SM prediction. This value is notably higher than the previous measurement averaged from the Tevatron and LEP experiments (M W = 80.385 ± 0.015 GeV) [24], as well as ATLAS (M W = 80.370 ± 0.019 MeV) [25] and LHCb 1 (M W = 80.354 ± 0.032 GeV) [26].…”

Third order fiducial predictions for Drell-Yan at the LHC

“…Among these, the production of a lepton pair (the Drell-Yan process) [1] arguably constitutes the most important standard candle at hadron colliders. The precise data collected at the LHC enables a broad spectrum of high-profile applications to different areas of particle physics, such as the extraction of Standard Model (SM) parameters [2][3][4][5][6], parton densities of the proton [7], and the exploration of beyond the Standard Model scenarios [8,9]. Today, the theoretical description of this important reaction reaches the highest level of accuracy.…”

“…Finally, the computation presented in this letter allows us to obtain, for the first time, N 3 LO+N 3 LL predictions for the kinematical distributions of the final-state leptons. A particularly relevant distribution is the leptonic transverse momentum, which plays a central role in the precise extraction of the W -boson mass at the LHC [2,6]. Fig.…”

The PDF4LHC21 combination of global PDF fits for the LHC Run III

“…Uncertainties associated with our limited knowledge of the quark and gluon structure of the proton, encoded by its collinear unpolarised parton distribution functions (PDFs), represent one of the most significant limiting factors in the theoretical interpretation of crucial processes at the LHC. These include the extraction of fundamental Standard Model (SM) parameters such as Higgs boson coupling measurements [1], the W -boson mass [2][3][4] and the strong coupling constant α s (m Z ), as well as direct BSM searches for heavy resonances [5] and indirect BSM searches via effective field theory [6,7]. Despite encouraging progress from first-principles lattice QCD calculations [8,9], the dominant paradigm for PDF determinations remains their phenomenological extraction from a global QCD analysis [10][11][12][13] from a wide range of hard-scattering processes, see [14][15][16][17][18][19][20] for recent analyses.…”