| This dissertation describes an alternative method of measuring the W boson mass in DO experiment. Instead of extracting MW from the fitting of W → enu fast Monte Carlo simulations to W → enu data as in the standard method, we make the direct fit of transverse mass between W → enu data and Z → ee data. One of the two electrons from Z boson is treated as a neutrino in the calculation of transverse mass. In ratio method, the best fitted scale factor corresponds to the ratio of W and Z boson mass (MW/M Z). Given the precisely measured Z boson mass, W mass is directly fitted from W → enu and Z → ee data. This dissertation demonstrates that ratio method is a plausible method of measuring the W boson mass. With the 1 fb--1 DO Run IIa dataset, ratio method gives MW = 80435 +/- 43(stat) +/- 26(sys)MeV. |
