SEMILEPTONIC INCLUSIVE B-DECAYS AND THE DETERMINATION OF VERTICAL-BAR-V(UB) VERTICAL-BAR FROM QCD SUM-RULES

We calculate the electron spectrum of semileptonic decays of B mesons into noncharmed hadrons. The shape of the spectrum obtained from QCD s um rules is in general agreement with quark model calculations. At hig h electron energies the decrease of the spectrum is less steep than pr edicted by Altarelli et al. Our analysis yields a total decay rate GAM MA(B --> X(u)enuBAR) = (6.8 +/- 2.0) X 10(13) \V(ub)\2 s-1. For the sp ectrum integrated over electron energies in the interval 2.4 GeV less- than-or-equal-to E(e) less-than-or-equal-to 2.6 GeV in the laboratory frame we obtain GAMMA(B --> X(u)enuBAR) = (5.0 +/- 1.6) X 10(12) \V(ub )\2 s-1. Estimating all sorts of theoretical uncertainties, we obtain \V(ub)\ = 0.003 +/- 0.001 for the b --> u weak transition matrix eleme nt from the new CLEO data.