Inclusive $B \to X_c l \nu$ decay spectra at Belle and the determination of $|V_{cb}|$

Abstract

We report measurements of the inclusive electron energy spectrum and hadron invariant mass spectrum for charmed semileptonic decays of B mesons in a 140 fb^-1 data sample collected with the Belle detector at the KEKB e+e- collider. We determine the first four central moments and partial branching fraction of the electron energy spectrum for electron energy thresholds from 0.4 to 2.0 GeV, and the first two central and second non-central moments of the hadron invariant mass spectrum for lepton energy thresholds from 0.7 to 1.9 GeV. Using these measurements and Belle measurements of the photon energy moments in B -> X_s gamma decays, we determine the CKM matrix element |Vcb|, the b quark mass and higher order non-perturbative parameters that appear in the Heavy Quark Expansion by performing a global fit analysis in the kinetic mass and 1S schemes.