ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2008, vol. 100, p. -
Observation of Bs0→φγ and search for Bs0→γγ decays at belle
We search for the radiative penguin decays Bs0→ γ and Bs0→γγ in a 23.6fb-1 data sample collected at the Υ(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 Bs0 meson in the Bs0→ γ mode and we measure B(Bs0→γ)=(57-15+18(stat)- 11+12(syst))×10-6. No significant Bs0→γγ signal is observed and we set a 90% confidence level upper limit of B(Bs0→γ γ)<8.7×10-6. © 2008 The American Physical Society.