Measurement and interpretation of moments in inclusive semileptonic decays ¯¯¯B→Xcℓ−¯ν

Abstract

We present results for the moments of observed spectra in inclusive semileptonic B -meson decays to charm hadrons ¯¯¯ B → X c ℓ − ¯ ν . Moments of the hadronic-mass and the combined mass-and-energy spectra for different minimum electron or muon momenta between 0.8 and 1.9 GeV / c are obtained from a sample of 232 × 10 6 Υ ( 4 S ) → B ¯¯¯ B events, collected with the BABAR detector at the PEP-II asymmetric-energy B -meson factory at SLAC. We also present a reevaluation of the moments of electron-energy spectra and partial decay fractions B ( ¯¯¯ B → X c e − ¯ ν ) for minimum electron momenta between 0.6 and 1.5 GeV / c based on a sample of 51 × 10 6 Υ ( 4 S ) → B ¯¯¯ B events. The measurements are used for the extraction of the total decay fraction, the Cabibbo-Kobayashi-Maskawa (CKM) matrix element | V c b | , the quark masses m b and m c , and four heavy-quark QCD parameters in the framework of a Heavy-Quark Expansion (HQE). We find B ( ¯¯¯ B → X c ℓ − ¯ ν ) = ( 10.64 ± 0.17 ± 0.06 ) % and | V c b | = ( 42.05 ± 0.45 ± 0.70 ) × 10 − 3 .