Weak radiative B decays

We study the (tree-level) weak radiative decays of B mesons. We present a numerical estimate for the inclusive b→Xcγ(γ) modes based on the free-quark decay. We then review what is known for the B→Dγ modes in the framework of heavy quark effective theory and chiral perturbation theory. Finally, we extend these ideas to the double radiative decay modes B→Dγγ. We find that the b→Xcγγ rate is about an order of magnitude larger than the corresponding b→Xsγγ rate. We also find the branching ratio for the B→Dγγ mode with most favorable CKM angles at the few×10-8 level, comparable to predictions for B→Kγγ.