Measurement of the mass of the W boson at LEP and determination of electroweak parameters

Precise measurements of the W mass and width performed at LEP are presented, which yield $M_W$ = 80.427 ± 0.046 GeV and $Γ_W$ = 2.12 ± 0.11 GeV. A comparison is made between this direct determination and the W mass value obtained indirectly in an analysis of other electroweak measurements. Good agreement is observed. All electroweak data are very consistent with the Standard Model predictions. In a combined fit an upper limit on the mass of the Higgs boson is put to $M_H$ < 203 GeV at 95% confidence level.