Two - Loop O ( α s G F m 2 t ) Correction to the H → bb̄ Decay Rate
نویسندگان
چکیده
We present the two-loop O(αsGFmt ) correction to the bb̄ decay rate of the Standard-Model Higgs boson, assuming that the t quark is much heavier than the Higgs boson. Apart from the universal correction connected with the renormalizations of the wave function and the vacuum expectation value of the Higgs field, this involves vertex corrections specific to the presence of beauty in the final state. We calculate the latter by means of a low-energy theorem. All would-be mass singularities related to the b quark can be absorbed into the running Higgs-bottom Yukawa coupling. It turns out that the total O(αsGFmt ) correction screens the leading high-mt behaviour of the one-loop result by 71% to 75% for MH between 60 GeV and 2MW . 1
منابع مشابه
Corrections of Order O ( G F α s m 2 t ) to the Higgs Decay Rate Γ ( H →
QCD corrections to the electroweak one-loop result for the partial width Γ(H → b ¯ b) are studied. For the decay channel into bottom quarks the rate is affected by a virtual top quark through electroweak interactions. The calculation of QCD corrections to this quantity is performed for an intermediate range Higgs mass in the heavy top mass limit. The leading correction of order O(G F α s m 2 t)...
متن کاملar X iv : h ep - p h / 96 05 31 0 v 2 1 3 O ct 1 99 6 O ( α 2 G F m 2 t ) Contributions to H → γγ
The rare decay H → γγ is a promising detection channel for an intermediate mass Higgs boson. We compute its two-loop O(αGFm 2 t ) correction in the standard model and find that the relative correction to the decay rate runs between 0.7% and 0.5% for MH = 80− 150 GeV. The analogous correction to the amplitude for gg → H is recovered as a special case. The generalization of our result to other mo...
متن کاملar X iv : h ep - p h / 96 05 31 0 v 1 1 5 M ay 1 99 6 O ( α 2 G F m 2 t ) Contributions to H → γγ
The rare decay H → γγ is a promising detection channel for an intermediate mass Higgs boson. We compute its two-loop O(αGFm 2 t ) correction in the standard model and find that it is much smaller than the corresponding QCD correction. The analogous correction to the amplitude for gg → H is recovered as a special case. The generalization of our result to other models is also briefly indicated.
متن کاملRate Induced by the Top Quark
We present the two-loop QED and QCD corrections to the f f̄H Yukawa coupling that are induced by the exchange of a virtual photon or gluon, respectively, with a heavy-fermion loop inserted. As an application, we study the corresponding O(αsM H/mt ) correction to the H → bb̄ decay rate. A Higgs boson with MH ∼< 135 GeV decays dominantly to bb̄ pairs [1]. This decay mode will be of prime importance ...
متن کاملNon-singlet Corrections of O(α 2 S G F M
The partial decay rate of the Z boson into bottom quarks constitutes an important decay channel. This is mainly due to the virtual presence of the top quark in the loop diagrams giving rise to correction factors which are quadratic in the top quark mass. At one-and two-loop order it turned out that the leading term in the heavy-top expansion leads to very good approximations to the exact result...
متن کامل