B→Xsγγ and Bs→γγ in supersymmetry with broken R parity

We examine the effects of R-parity violating (RPV) supersymmetry on the two-photon B decays B→Xsγγ and Bs→γγ. We find that, although there are many one-loop RPV diagrams, which can contribute to these two-photon B decays, the RPV effect is dominated by a single diagram. This diagram, named here λ-irreducible, has a distinct topology, which is irrelevant for the b→sγ amplitude at one-loop, and has thus a negligible effect on the one-photon decay B→Xsγ. We show that the λ-irreducible RPV diagram can give BR(Bs→γγ)∼5x10-6 and BR(B→Xsγγ)∼6x10-7, which is about 16 and 5 times larger than the SM values, respectively. Although the enhancement to the decay width of B→Xsγγ is not that dramatic, we find that the energy distribution of the two photons is appreciably different from the SM, due to new threshold effects caused by the distinct topology of the RPV λ-irreducible diagram. Moreover, this diagram significantly changes the forward-backward asymmetry with respect to the softer photon in B→Xsγγ. Thus, the RPV effect in B→Xsγγ can be discerned using these observables