The mW - mZ interdependence in the Standard Model: a new scrutiny

The m(W) - m(Z) interdependence in the Standard Model is studied in the MS scheme at the two-loop level, including the known higher-order contributions. The relevant radiative parameters, Delta(alpha) over cap(mu), Delta(r) over cap (W), (rho) over cap are computed at O(alpha(2)) taking into account high-rorder QCD corrections and the resummation of the reducible contributions. We obtain m(W) = 80.357 +/- 0.009 +/- 0.003 GeV where the errors refer to the parametric and theoretical uncertainties, respectively. A comparison with the known result in the On-Shell scheme gives a difference of approximate to 6 MeV. As a byproduct of our calculation we also obtain the (MS) over bar electromagnetic coupling and the weak mixing angle at the top mass scale, (alpha) over cap (M-t) = (127.73)(-1) +/- 0.0000003 and sin(2)(theta) over cap (W) (Mt) = 0.23462 +/- 0.00012.