| Measurements of the mass and width of the W boson are performed using ∫ L dt = 183 pb-1 of data recorded at s = 189 GeV from the OPAL experiment at LEP. The reconstructed invariant mass distributions from 970 W+W- → qq¯qq¯ and 1118 W+W- → qq¯ ℓnℓ events are used to extract the W mass, assuming the Standard Model relation between the W boson mass and width: MW=80.440+/-0.075 stat.+/-0.042 syst.GeV.;A direct measurement of the width of the W boson gives: GW=2.082+/-0.185 stat.+/-0.100 syst.GeV. |
