Updated Next-to-Next-to-Leading-Order QCD Predictions for the Weak Radiative B -Meson Decays

Abstract

Weak radiative decays of the B mesons belong to the most important flavor changing processes that provide constraints on physics at the TeV scale. In the derivation of such constraints, accurate standard model predictions for the inclusive branching ratios play a crucial role. In the current Letter we present an update of these predictions, incorporating all our results for the O(α_{s}^{2}) and lower-order perturbative corrections that have been calculated after 2006. New estimates of nonperturbative effects are taken into account, too. For the CP- and isospin-averaged branching ratios, we find B_{sγ}=(3.36±0.23)×10^{-4} and B_{dγ}=(1.73_{-0.22}^{+0.12})×10^{-5}, for E_{γ}>1.6 GeV. Both results remain in agreement with the current experimental averages. Normalizing their sum to the inclusive semileptonic branching ratio, we obtain R_{γ}≡(B_{sγ}+B_{dγ})/B_{cℓν}=(3.31±0.22)×10^{-3}. A new bound from B_{sγ} on the charged Higgs boson mass in the two-Higgs-doublet-model II reads M_{H^{±}}>480 GeV at 95% C.L.

Anomalous triple gauge couplings from B-meson and kaon observables

“…terms of the shift ∆C 7 , the ratio between the new-physics branching ratio of B → X s γ and the SM prediction can be written as [37] …”

Strong first order electroweak phase transition in the CP-conserving 2HDM revisited

“…The consistency with the EW precision constraints has been checked through the oblique parameters S, T and U [85] by applying the general procedure for extended Higgs sectors as described in [86,87] and demanding for compatibility with the SM fit [88] within 2σ, including correlations. Constraints applied to the charged sector of the 2HDM are based on results from the measurement of R b [89,90] and B → X s γ [90][91][92] including the recent calculation [93] [98][99][100]. This program includes the state-of-the-art higher order QCD corrections and off-shell decays.…”

Analysis of the TeV-scale mirage mediation with heavy superparticles

“…Then, we can evade the strong bounds from flavor physics. It is known that the stringent bound on this kind of model comes from the rare B meson decays: B → X s γ [66][67][68] and B s → µ + µ − [69,70]. If there is only one extra Higgs doublet that couples to the right-handed down-type quarks as in the type-II 2HDM, there is an one-loop correction involving charged Higgs which does not depend on tan β.…”

“…We adopt the experimental values as follows: Br(b → sγ) exp = (3.32 ± 0.16) × 10 −4 for E γ > 1.6 GeV [77] and Br(B s → µ + µ − ) exp = (3.00 ± 0.55) × 10 −9 [70,78,79]. The SM predictions we use are Br(b → sγ) SM = (3.36 ± 0.23) × 10 −4 for E γ > 1.6 GeV [67] and Br(B s → µ + µ − ) SM = (3.60 ± 0.18) × 10 −9 [70].…”