THE EFFECTS OF THE QCD CORRECTIONS TO $\Gamma \left( {H^0 \to b\bar b} \right)$

Abstract

We consider in detail various theoretical uncertainties of the perturbative predictions for the decay width of [Formula: see text] process in the region 60 GeV<MH≤2 MW. We calculate the order [Formula: see text]-contributions to the expression for [Formula: see text] through the pole b-quark mass mb and demonstrate that they are important for the elimination of the numerical difference between the corresponding expression and the renormalization-group (RG) which can be improved by the running b-quark mass. In the case of mb=4.8 GeV and [Formula: see text] we observe the identical cancellation of the next-to-leading order RG-improved corrections to [Formula: see text] at Mch=130 (65) GeV and the indications to the asymptotic explosion of the corresponding next-to-next-to-leading parametrization. The theoretical importance of the order [Formula: see text] massive corrections [Formula: see text] to for modeling the threshold effects is demonstrated.