Abstract :
The electroweak 1-loop corrections to the decay width of the W boson into fermions Λ(W+ → f1 f2) are discussed in the extended Higgs sector of the general two Higgs doublet model without any constraint. The relative corrections to the decay W+ → e+νe which come exclusively from W boson propagator are unobservably small in the whole parameter region with the maximal correction of −6 × 10−3%. Due to the increasing of the Yukawa couplings with fermion masses, the relative corrections to the decays W+→ τ+ντ and W+ → cs become larger, but even after having raised the Yukawa couplings with help of tanβ, the maximal corrections lie under the percent region and thus give also no observable effect. We discuss also the Higgs sector of the minimal supersymmetric standard model for the decays W+→ τ+ντ and W+ → cs. Similarly to the cases in the general two Higgs doublet model, the corrections in this model give no sizable effect and hence are not significant.
