Measurement of the B ¯ →xsγ branching fraction with a sum of exclusive decays MEASUREMENT of THE. T. SAITO et al.

Abstract

We use 772×106 BB¯ meson pairs collected at the ?(4S) resonance with the Belle detector to measure the branching fraction for B¯→Xsγ. Our measurement uses a sum-of-exclusives approach in which 38 of the hadronic final states with strangeness equal to +1, denoted by Xs, are reconstructed. The inclusive branching fraction for MXs<2.8GeV/c2, which corresponds to a minimum photon energy of 1.9 GeV, is measured to be B(B¯→Xsγ)=(3.51±0.17±0.33)×10-4, where the first uncertainty is statistical and the second is systematic.