A Measurement of the W Boson Mass

We present a measurement of the W boson mass using data collected by the D0 experiment at the Fermilab Tevatron during 1994--1995. We identify W bosons by their decays to $e\nu$ final states. We extract the W mass, M(W), by fitting the transverse mass and transverse electron momentum spectra from a sample of 28,323 W to $e\nu$ decay candidates. We use a sample of 3,563 dielectron events, mostly due to Z to ee decays, to constrain our model of the detector response. From the transverse mass fit we measure M(W) = $80.44\pm0.10(stat)\pm0.07(syst)$ GeV. Combining this with our previously published result from data taken in 1992--1993, we obtain M(W) $= 80.43\pm0.11$ GeV.