Measurement of the moments of the photon energy spectrum in B -> X-s gamma decays and determination of |V-cb| and m(b) at Belle

Abstract

Using the previous Belle measurement of the inclusive photon energy in B -> X-s gamma decays, we determine the first and second moments of this spectrum for minimum photon energies in the B meson rest frame ranging from 1.8 to 2.3 GeV. Combining these measurements with recent Belle data on the lepton energy and hadronic mass moments in B -> X-c center dot nu decays, we perform fits to theoretical expressions derived in the 1S and kinetic mass schemes and extract the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V-cb, the b-quark mass, and other nonperturbative parameters. In the 1S scheme analysis we find |V-cb|=(41.56 +/- 0.68(fit)+/- 0.08(tau(B)))x10(-3) and m(b)(1S)=(4.723 +/- 0.055) GeV. In the kinetic scheme, we obtain |V-cb|=(41.58 +/- 0.69(fit)+/- 0.08(tau(B))+/- 0.58(th))x10(-3) and m(b)(kin)=(4.543 +/- 0.075) GeV.