Evidence for penguin-diagram decays: First observation of B→K*(892)γ

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