Three-loop O(αs2GFMt2) corrections to Higgs production and decay at e+e− colliders

Kniehl, Bernd A.; Steinhauser, Matthias

doi:10.1016/0550-3213(95)00441-t

Cited by 33 publications

(50 citation statements)

References 62 publications

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“…(15) we read off that the leading O(X t ) term receives the QCD correction factor (1 − 0.333 A 6 − 11.219 A 2 6 ). We thus recover a pattern similar to the electroweak parameter ∆ρ [21] and the corrections δ u , δ W W H , and δ ZZH [19] to the l + l − H, W + W − H, and ZZH vertices, respectively. In fact, the corresponding QCD expansions in A 6 of these four observables all have negative coefficients which dramatically increase in magnitude as one passes from two to three loops [19].…”

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confidence: 80%

“…We thus recover a pattern similar to the electroweak parameter ∆ρ [21] and the corrections δ u , δ W W H , and δ ZZH [19] to the l + l − H, W + W − H, and ZZH vertices, respectively. In fact, the corresponding QCD expansions in A 6 of these four observables all have negative coefficients which dramatically increase in magnitude as one passes from two to three loops [19]. On the other hand, if the top-quark mass is renormalized in the MS scheme at scale µ = µ t , then the respective QCD expansions in a 6 are found to have coefficients which have variant signs and nicely group themselves around zero [19].…”

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confidence: 80%

“…An analytic expression forδ u , valid for µ and N c arbitrary, may be found in Ref. [19]. As mentioned above, C 1 and C 2b are RG invariant per construction.…”

mentioning

confidence: 99%

“…In fact, the corresponding QCD expansions in A 6 of these four observables all have negative coefficients which dramatically increase in magnitude as one passes from two to three loops [19]. On the other hand, if the top-quark mass is renormalized in the MS scheme at scale µ = µ t , then the respective QCD expansions in a 6 are found to have coefficients which have variant signs and nicely group themselves around zero [19]. We note in passing that the study of infrared renormalons [22] offers a possible theoretical explanation for this observation.…”

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confidence: 99%

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Virtual Top-Quark Effects on theH→bb¯Decay at Next-to-Leading Order in QCD

1997

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By means of a heavy-top-quark effective Lagrangian, we calculate the three-loop corrections of O(α 2 s G F M 2 t ) to the H → bb partial decay width of the standardmodel Higgs boson with intermediate mass M H ≪ 2M t . We take advantage of a soft-Higgs theorem to construct the relevant coefficient functions. We present our result both in the MS and on-shell schemes of mass renormalization. The MS formulation turns out to be favourable with regard to the convergence behaviour. We also test a recent idea concerning the naïve non-abelianization of QCD.

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confidence: 80%

mentioning

confidence: 80%

“…An analytic expression forδ u , valid for µ and N c arbitrary, may be found in Ref. [19]. As mentioned above, C 1 and C 2b are RG invariant per construction.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Virtual Top-Quark Effects on theH→bb¯Decay at Next-to-Leading Order in QCD

1997

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“…(4.16). In particular, the universal corrections δ u arise from the renormalization of the factor H 0 /v 0 and are known to order α 2 s G F m 2 t [77]. The factors ∆ ij contain the QED and QCD corrections from the light degrees of freedom only, while the terms ∆ hdo summarize the corrections coming from higher dimensional operators.…”

Section: Hadronic Decay Rate Of the Sm Higgs Bosonmentioning

confidence: 99%

Results and techniques of multi-loop calculations

Steinhauser

2002

Physics Reports

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100

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In this review some recent multi-loop results obtained in the framework of perturbative Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED) are discussed. After reviewing the most advanced techniques used for the computation of renormalization group functions, we consider the decoupling of heavy quarks. In particular, an effective method for the evaluation of the decoupling constants is presented and explicit results are given. Furthermore the connection to observables involving a scalar Higgs boson is worked out in detail. An all-order low energy theorem is derived which establishes a relation between the coefficient functions in the hadronic Higgs decay and the decoupling constants. We review the radiative corrections of a Higgs boson into gluons and quarks and present explicit results up to order α 4 s and α 3 s , respectively. In this review special emphasis is put on the applications of asymptotic expansions. A method is described which combines expansion terms of different kinematical regions with the help of conformal mapping and Padé approximation. This method allows us to proceed beyond the present scope of exact multi-loop calculations. As far as physical processes are concerned, we review the computation of three-loop current correlators in QCD taking into account the full mass-dependence. In particular, we concentrate on the evaluation of the total cross section for the production of hadrons in e + e − annihilation. The knowledge of the complete mass dependence at order α 2 s has triggered a bunch of theory-driven analyses of the hadronic contribution to the electromagnetic coupling evaluated at high energy scales. The status is summarized in this review. In a further application four-loop diagrams are considered which contribute to the order α 2 QED corrections to the µ decay. Its relevance for the determination of the Fermi constant G F is discussed. Finally the calculation of the three-loop relation between the MS and on-shell quark mass definitions is presented and physical applications are given. To complete the presentation, some technical details are presented in the Appendix, where also explicit analytical results are listed.

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Dependence of electroweak parameters on the definition of the top-quark mass

Kniehl

1996

Z. Phys. C - Particles and Fields

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The QCD corrections to electroweak parameters depend on the renormalization scheme and scales used to define the top-quark mass. We analyze these dependences for the W -boson mass predicted via ∆r to O(αα s ) and O(αα 2 s ) in the on-shell and MS schemes. These variations provide us with a hint on the magnitude of the unknown higher-order QCD effects and contribute to the theoretical error of the prediction.

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Three-loop O(αs2GFMt2) corrections to Higgs production and decay at e+e− colliders

Cited by 33 publications

References 62 publications

Virtual Top-Quark Effects on theH→bb¯Decay at Next-to-Leading Order in QCD

Virtual Top-Quark Effects on theH→bb¯Decay at Next-to-Leading Order in QCD

Results and techniques of multi-loop calculations

Dependence of electroweak parameters on the definition of the top-quark mass

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