Measurement of the W Boson Mass Using Electrons at Large Rapidities

We report a measurement of the W boson mass based on an integrated luminosity of 82pb^-1 from pp̄ collisions at √s0ex0ex=0ex0ex1.8TeV recorded in 1994--1995 by the D0 detector at the Fermilab Tevatron. We identify W bosons by their decays to eν, where the electron is detected in the forward calorimeters. We extract the mass by fitting the transverse mass and the electron and neutrino transverse momentum spectra of 11 089 W boson candidates. We measure MW0ex0ex=0ex0ex80.691±0.227GeV. By combining this measurement with our previously published central calorimeter results from data taken in 1992--1993 and 1994--1995, we obtain MW0ex0ex=0ex0ex80.482±0.091GeV.