Measurement of the W-boson mass at LEP

In 1997 each LEP experiment recorded approximately 55 pb/sup -1/ of data at mean centre-of-mass energy of 183 GeV. The experimental details of the measurement of the mass of the W-boson in the fully hadronic final state (W/sup +/W/sup -/ to qqqq) are described. This result is combined with the measurement obtained from W/sup +/W/sup - / to qql nu /sub l/ events. The LEP combined result, obtained from all data recorded above the W-pair production threshold, assuming the standard model relation between the W-boson decay width and mass, is M/sub W/=80.37+or-0.07(exp)+or-0.04(FSI)+or-0.02(E/sub beam/). This result is consistent with the indirect determination of M/sub W/ from fits to Z/sup 0/ data obtained at LEP and SLC. (13 refs).