Observation of Bs0→φγ and search for Bs0→γγ decays at belle

We search for the radiative penguin decays B 0 S →Oγ and B 0 →, γγ in a 23.6 fb -1 data sample collected at the Y(5S) resonance with the Belle detector at the KEKB e + e - asymmetric-energy collider. We observe for the first time a radiative penguin decay of the B 0 S meson in the B 0 s →Oγ mode and we measure Β(B 0 S →Oγ) = (57 + -15 18 (stat)+12 -11 (syst)) X 10 -6 . No significant B 0 → γγ signal is observed and we set a 90% confidence level upper limit of B(Bs 0 → γγ) < 8.7 X 10 -6 .