Three-Loop O(alphaₛ² GF Mₜ²) Corrections to Hadronic Higgs Decays

الأصل · EN

We calculate the top-quark-induced three-loop corrections of O(alphaₛ² GF Mₜ²) to the Yukawa couplings of the first five quark flavours in the framework of the minimal standard model with an intermediate-mass Higgs boson, with mass Mₕ << 2Mₜ. The calculation is performed using an effective-Lagrangian approach implemented with the hard-mass procedure. As an application, we derive the O(alphaₛ² GF Mₜ²) corrections to the H -> q q-bar partial decay widths, including the case q=b. The couplings of the Higgs boson to pairs of leptons and intermediate bosons being known to O(alphaₛ² GF Mₜ²), this completes the knowledge of such corrections in the Higgs sector. We express the results both in the MS-bar and on-shell schemes of mass renormalization. We recover the notion that the QCD perturbation expansions exhibit a worse convergence behaviour in the on-shell scheme than they do in the MS-bar scheme.