Measurement of inclusive radiative B-meson decays with a photon energy threshold of 1.7 GeV

Using 605fb-1 of data collected at the Υ(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B→Xsγ. For the lower photon energy thresholds of 1.7, 1.8, 1.9, and 2.0 GeV, as defined in the rest frame of the B meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7 GeV threshold we obtain the partial branching fraction BF(B→Xsγ)=(3.45±0. 15±0.40)×10-4, where the errors are statistical and systematic. © 2009 The American Physical Society.