Measurement of the Electron Energy Spectrum and its Moments in Inclusive B->X e nu Decays

Abstract

We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million Y4S -> BBar decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cut-offs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be Br(B -> X e nu, E_e>0.6 GeV) = (10.36 +-0.06(stat.) +-0.23(sys))%.

Figures (3)

• Figure 1: Measured momentum spectrum (points) and estimated backgrounds (histograms) for electron candidates in (a) the unlike-sign sample, and (b) the like-sign sample.
• Figure 2: Electron momentum spectrum from $B\xspace \rightarrow\xspace X e \nu (\gamma)$ decays in the $\Upsilon(4S)$ frame after correction for efficiencies and bremsstrahlung, with combined statistical and systematic errors.
• Figure 3: Measured moments of the inclusive electron energy spectrum of $B\xspace \rightarrow\xspace X_c e \nu (\gamma)$ decays as a function of the cut-off energy, (a) ${\cal B}$, (b) $M_1$, (c) $M_2$ and (d) $M_3$.