Observation of BS0→φγ and search for BS0→γγ decays at Belle

We search for the radiative penguin decays B(s)(0)->phi gamma and B(s)(0)->gamma gamma in a 23.6 fb(-1) data sample collected at the Upsilon(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(s)(0) meson in the B(s)(0)->phi gamma mode and we measure B(B(s)(0)->phi gamma)=(57(-15)(+18)(stat)(-11)(+12)(syst))x10(-6). No significant B(s)(0)->gamma gamma signal is observed and we set a 90% confidence level upper limit of B(B(s)(0)->gamma gamma)< 8.7x10(-6).