Du, DS (reprint author), CCAST,WORLD LAB,POB 8730,BEIJING 100080,PEOPLES R CHINA.
We study the decay B-c --> D-s*gamma. There are two mechanisms contributing to the process. One proceeds through the short distance b --> s gamma 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 x 10(-18) GeV. In particular, we find the contribution of the weak annihilation is 6.25 x 10(-18) GeV which is in the same order as that of the electromagnetic penguin. The total decay rate Gamma(B-c --> D-s*gamma) is predicted to be 1.45 x 10(-17) GeV and the branching ratio Br(B-c --> D-s*gamma)is predicted to be 2.98 x 10(-5) for tau(Bc) = 1.35 ps. The the decays B-c --> D-s*gamma can be well studied at LHC in the near future.