Annihilation Type Radiative Decays of $B$ Meson in Perturbative QCD Approach

Abstract

With the perturbative QCD approach based on $k_T$ factorization, we study the pure annihilation type radiative decays $B^0\to \varphi \gamma$ and $B^0\to J/\psi \gamma$. We find that the branching ratio of $B^0\to \varphi \gamma$ is $(2.7_{-0.6-0.6}^{+0.3+1.2})\times 10^{-11}$, which is too small to be measured in the current $B$ factories of BaBar and Belle. The branching ratio of $B^0\to J/\psi \gamma$ is $(4.5_{-0.5-0.6}^{+0.6+0.7})\times 10^{-7}$, which is just at the corner of being observable in the $B$ factories. A larger branching ratio $BR(B_s^0\to J/\psi \gamma )\simeq 5\times 10^{-6}$ is also predicted. These decay modes will help us testing the standard model and searching for new physics signals.

Comments: 4 pages, revtex, with 1 eps figure