Abstract:
We present a measurement of the W boson mass using data
collected by the DØ experiment at the Fermilab Tevatron
during 1994-1995. We identify W bosons by their decays to
enu final states where the electron is detected in a forward
calorimeter. We extract the W boson mass MW by fitting the
transverse mass and transverse electron and neutrino
momentum spectra from a sample of 11089 W->enu decay
candidates. We use a sample of 1687 dielectron events,
mostly due to Z->ee decays, to constrain our model of the
detector response. Using the forward calorimeter data, we
measure MW = 80.691±0.227 GeV.