The m W − m Z interdependence in the Standard Model: a new scrutiny

The mW−mZ interdependence in the Standard Model is studied at O(α2) in the MSbar scheme. The relevant radiative parameters, Δα^(μ),Δr^W,ρ^ are computed at the full two-loop level augmented by higher-order QCD contributions and by resummation of reducible contributions. We obtain mW=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 ≈6 MeV. As a byproduct of our calculation we also obtain the MS⎯⎯⎯⎯⎯⎯ electromagnetic coupling and the Weinberg angle at the top mass scale, α^(Mt)=(127.73)−1±0.0000003 and sin2θ^W(Mt)=0.23462±0.00012.