CP asymmetries in b→(s/d) transitions as a test of CKM CP violation

We point out that a simple test of the mechanism of CP violation can be performed by a measurement of the CP asymmetries in exclusive and inclusive radiative rare decays. We show that the rate asymmetries ΔΓ=Γ(B−→fγ)−Γ(B+→f̄γ) for certain final states f can be predicted in a theoretically clean way. Some implications for b→sℓ+ℓ− decays are discussed.