We have observed the decays ${\mathit{B}}^0$→${\mathit{K}}^{\mathrm{*}}$(892${)}^0$γ and ${\mathit{B}}^{\mathrm{-}}$→${\mathit{K}}^{\mathrm{*}}$(892${)}^{\mathrm{-}}$γ, which are evidence for the quark-level process b→sγ. The average branching fraction is (4.5±1.5±0.9)×${10}^{\mathrm{-}5}$. This value is consistent with standard model predictions from electromagnetic penguin diagrams.

• Received 24 May 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.674