Annihilation type radiative decays of B meson in perturbative QCD approach

With the perturbative QCD approach based on k_T factorization, we study the pure annihilation type radiative decays B⁰→ϕγ and B⁰→J/ψγ. We find that the branching ratio of B⁰→ϕγ is (2.7_-0.6-0.6^+0.3+1.2)×10^-11, which is too small to be measured in the current B factories of BABAR and Belle. The branching ratio of B⁰→J/ψγ is (4.5_-0.5-0.6^+0.6+0.7)×10^-7, which is just at the corner of being observable in the B factories. A larger branching ratio BR(B_s⁰→J/ψγ)≃5×10^-6 is also predicted. These decay modes will help us in testing the standard model and searching for new physics signals.