The rare $\bar{B}^0_{d} \to ϕγ$ decays in Standard Model and as a probe of R-parity violation

Abstract

We present the first study of the rare annihilation decay $\bar{B}^0_d \to ϕγ$ in the Standard Model. Using QCD factorization formalism, we find ${\cal B}(\bar{B}^0_d \toϕγ)=3.6\times 10^{-12}$. The smallness of the decay rate in the Standard Model make the decay a sensitive probe of new physics contributions. As an example, we calculate the effects of R-parity violating couplings. Within the available upper bounds for $|λ^{''}_{i23}λ^{''}_{i12}|$ and $|λ^{'}_{i32}λ^{'*}_{i12}|$, ${\cal B}(\bar{B}^0_d \toϕγ)$ could be enhanced to order of $10^{-9}\sim 10^{-8}$, which might be accessible at LHCB, B-TeV and the planning super high luminosity B factories at KEK and SLAC.