The Effects of the Massless O(alphaₛ²), O(ααₛ), O(α²) QCD and QED Corrections and of the Massive Contributions to Gamma(H⁰→ bb)

الأصل · EN

We consider in detail various theoretical uncertainties of the perturbative predictions for the decay width of H⁰→ bb process in the region 50GeV< 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.