B⁺→D_s*⁺ γ and B⁺→D*⁺ γ as probes of V_ub

The decays B⁺→D_s*⁺ γ and B⁺→D*⁺ γ can be used for an extraction of |V_ub|. When the b and c quarks are nearly degenerate, the rate for these modes can be determined in terms of other observed rates, namely BB̄ mixing and D*→Dγ decay. To this end, we introduce a novel application of heavy quark and flavor symmetries. Although somewhat unrealistic, this limit provides us with a first estimate of these rates.