A study on the rare radiative decay

Abstract

We study the decay B c → D * s γ. There are two mechanisms contributing to the process. One proceeds through the short distance b→sγ transition and the other occurs through weak annihilation accompanied by a photon emission. The electromagnetic penguin contribution is estimated by perturbative QCD and found to be 4.68 × 10 −18 GeV . In particular, we find the contribution of the weak annihilation is 6.25 × 10 −18 GeV which is in the same order as that of the electromagnetic penguin.The total decay rate Γ(B c → D * s γ) is predicted to be 1.45 × 10 −17 GeV and the branching ratio Br(B c → D * s γ) is predicted to be 2.98 × 10 −5 for τ Bc = 1.35ps. The the decays B c → D * s γ can be well studied at LHC in the near future.

The study of rare $ {B_c}\to D_{s,d}^{{\left( * \right)}}l\overline{l} $ decays

“…(2.21)-(2.25) and shown in figures 6-13. In our calculation, if only Q 7 and Ann contributions are considered, we find that the relationship dBr [20][21][22], the same relationship also holds.…”

“…[17][18][19] only the b → s(d)ll short-distance contribution is considered. Recently, using the annihilation form-factors of B c → D * s γ [20][21][22], the B c → D * s ll transitions combined with the annihilation effects have been analysed…”

Rare radiative decays of theBcmeson

“…For instance, in Ref. [2], the Wilson coefficient C eff 7γ is obtained neglecting the mixing of O 7γ with other operators, while in Ref. [1], this approximation is not employed.…”

“…In the existing studies [1][2][3][4][5], the annihilation (Ann) and penguin (Peng) diagrams, as shown in Fig. 1, are paid attention to.…”

“…In Refs. [1,2], the hadronic matrix element corresponding to the penguin diagram is estimated by means of the perturbative QCD (pQCD), while the annihilation one is analyzed using the effective formalism [7]. In Ref.…”