Measurement of Mass and Width of the W Boson at LEP

Abstract

We report on measurements of the mass and total decay width of the W boson with the L3 detector at LEP. W-pair events produced in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ interactions between 161 GeV and 183 GeV centre-of-mass energy are selected in a data sample corresponding to a total luminosity of 76.7 pb${}^{-1}$. Combining all final states in W-pair production, the mass and total decay width of the W boson are determined to be ${\mathrm{M}}_{\mathrm{W}}=80.61\pm 0.15$ GeV and $\hat{I}{“}_{\mathrm{W}}=1.97\pm 0.38$ GeV, respectively.