Measurement of the<i>B</i>-meson inclusive semileptonic branching fraction and electron-energy moments

Abstract

We report a new measurement of the B-meson semileptonic decay momentum spectrum that has been made with a sample of 9.4 ${\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ data collected with the CLEO II detector at the $\ensuremath{\Upsilon}(4S)$ resonance. Electrons from primary semileptonic decays and secondary charm decays were separated by using charge and angular correlations in $\ensuremath{\Upsilon}(4S)$ events with a high-momentum lepton and an additional electron. We determined the semileptonic branching fraction to be $\mathcal{B}(\stackrel{\ensuremath{\rightarrow}}{B}{\mathrm{Xe}}^{+}{\ensuremath{\nu}}_{e})=(10.91\ifmmode\pm\else\textpm\fi{}0.09\ifmmode\pm\else\textpm\fi{}0.24)%$ from the normalization of the electron-energy spectrum. We also measured the moments of the electron-energy spectrum with minimum energies from 0.6 to 1.5 GeV.