Measurement of the W boson mass with the Collider Detector at Fermilab

Abstract

We present a measurement of the W boson mass using data collected with the CDF detector during the 1994--1995 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 30115 $\stackrel{\ensuremath{\rightarrow}}{W}e\ensuremath{\nu}$ events recorded in an integrated luminosity of 84 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ gives a mass ${M}_{W}=80.473\ifmmode\pm\else\textpm\fi{}0.065(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.092(\mathrm{syst})\mathrm{GeV}{/c}^{2}.$ A fit to the transverse mass spectrum of a sample of 14740 $\stackrel{\ensuremath{\rightarrow}}{W}\ensuremath{\mu}\ensuremath{\nu}$ events from 80 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ gives a mass ${M}_{W}=80.465\ifmmode\pm\else\textpm\fi{}0.100(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.103(\mathrm{syst})\mathrm{GeV}{/c}^{2}.$ The dominant contributions to the sys- tematic uncertainties are the uncertainties in the electron energy scale and the muon momentum scale, $0.075\mathrm{GeV}{/c}^{2}$ and $0.085\mathrm{GeV}{/c}^{2},$ respectively. The combined value for the electron and muon channel is ${M}_{W}=80.470\ifmmode\pm\else\textpm\fi{}0.089\mathrm{GeV}{/c}^{2}.$ When combined with previously published CDF measurements, we obtain ${M}_{W}=80.433\ifmmode\pm\else\textpm\fi{}0.079\mathrm{GeV}{/c}^{2}.$