The Effects of the Massless O(alpha_s^2), O(\alpha\alpha_s), O(\alpha^2)
QCD and QED Corrections and of the Massive Contributions to
Gamma(H^0\rightarrow b\overline{b})
We consider in detail various theoretical uncertainties of the perturbative
predictions for the decay width of H0→bb process in
the region 50 GeV<MH​≤2MW​. We calculate the order
O(αs2​)-contributions to the expression for ΓHbb​
through the pole quark mass and demonstrate that they are important for the
elimination of the numerical difference between the corresponding expression
and the one through the running b-quark mass. The order O(ααs​)
and O(α2) massless and order O(mb2​/MH2​) massive corrections to
ΓHbb​ are also calculated. The importance of the latter
contributions for modeling of the threshold effects is demonstrated. The
troubles with identifying of the 4 recent L3 events e+e−→l+l−γγ with the decay of a Standard Higgs boson are discussed.Comment: 16 pages, 6 figures (can be optained by mail after the request from
the authers, e-mails: [email protected]; [email protected]); LATEX,
modified version of ENSLAPP.-A.-407/92 preprin