M. Awramik

Precise prediction for the W boson mass in the standard model

The presently most accurate prediction for the W-boson mass in the standard model is obtained by combining the complete two-loop result with the known higher-order QCD and electroweak corrections. The numerical impact of the different contributions is analyzed in detail. A simple parametrization of the full result is presented, which approximates the full result for

Electroweak two-loop corrections to the effective weak mixing angle

{M}_{W}

Bosonic corrections to Delta r at the two loop level

to better than 0.5 MeV for

Bosonic corrections to the effective weak mixing angle at O(α2)

10\mathrm{GeV}l~{M}_{H}l~1\mathrm{TeV}

Two-loop electroweak fermionic corrections to sin2θeffbb¯

if the other parameters are varied within their combined 2\ensuremath{\sigma} region around their experimental central values. The different sources of remaining theoretical uncertainties are investigated. Their effect on the prediction of

Two-loop Fermionic Electroweak Corrections to the Effective Leptonic Weak Mixing Angle in the Standard Model

{M}_{W}

Bosonic corrections to the effective leptonic weak mixing angle at the two-loop level

is estimated to be about 4 MeV for

Two-loop electroweak fermionic corrections to sin^2 theta_{eff}^{b anti-b}

{M}_{H}\ensuremath{\lesssim}300\mathrm{GeV}.

Towards Better Constraints on the Higgs Boson Mass: Two-Loop Fermionic Corrections to sin^2(theta_eff)

Recently exact results for the complete electroweak two-loop contributions to the effective weak mixing angle were published. This paper illustrates the techniques used for this computation, in particular the methods for evaluating the loop diagrams and the proper definition of Z-pole observables at next-to-next-to-leading order. Numerical results are presented in terms of simple parametrization formulae and compared in detail with a previous result of an expansion up to next-to-leading order in the top-quark mass. Finally, an estimate of the remaining theoretical uncertainties from unknown higher-order corrections is given.