Download or read book Preliminary Measurement of the Inclusive Electron Spectrum in Charmless Semileptonic B Decays Near the Kinematic Endpoint and Determination of [verticalV[sub Ub][vertical written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors study the inclusive electron spectrum of B --> X[sub u]e[nu] decays near the kinematic limit for B --> X[sub c]e[nu] transitions using a sample of 88 million [Upsilon](4S) decays recorded by the BABAR detector at the PEP II e[sup +]e[sup -] storage rings. For the electron momentum interval of 2.0-2.6GeV/c the partial branching fraction is measured to be [Delta]B(B --> X[sub u]e[nu]) = (0.480 [+-] 0.029(stat) [+-] 0.053(syst) x 10[sup -3]). Combining this result on [Delta]B with measurements of the inclusive photon spectrum in B --> X[sub s][gamma] transition the authors find V[sub ub] = 3.94 [+-] 0.25exp [+-] 0.37 f[sub u] [+-] 0.19 theory x 10[sup -3], where the first error represents the combined statistical and systematic experimental uncertainty of the partial branching fraction measurement, the second refers to the uncertainty of the determination of the fraction f[sub u] of the inclusive electron spectrum that falls within the cuts, and the third error is due to theoretical uncertainties in the QCD corrections, plus the uncertainty in the b-quark mass. All results are preliminary.