A Measurement of theWBoson Mass at the Fermilabpp¯Collider

We report a measurement of the W boson mass based on an integrated luminosity of 82 pb −1 from pp collisions at √s = 1.8 TeV recorded in 1994-1995 by the D0 detector at the Fermilab Tevatron. We identify W bosons by their decays to e∨ V and extract the mass by fitting the transverse mass spectrum from 28 323 W boson candidates. A sample of 3563 dielectron events, mostly due to Z→ee decays, constrains models of W boson production and the detector. We measure M W = 80.44±0.10(stat)±0.07(syst) GeV. By combining this measurement with our result form the 1992-1993 data set, we obtain M W = 80.43±0.11 GeV.