A. Fridman

The Electron Spectrum From B-meson Decays

The Crystal Ball Collaboration has measured the energy spectrum of electrons from semileptonicB meson decays at thee+e− storage ring DORIS II. Branching ratios and weak mixing angles of the Kobayashi-Maskawa matrix are determined using several models for the hadronic matrix elements. We obtain the branching ratio for semileptonic.B decays to charmed states BR(B→evXc)=(11.7±0.4±1.0)%. Our result for the corresponding Kobayashi-Maskawa matrix element is |Vcb|=0.052±0.006. The model dependence of both results is included in the error. We have not observed semileptonicB decays to non-charmed mesons. Analyzing the measured electron spectrum above 2.4 GeV, where nob→c decays contribute, we find BR(B→evXu)/BR(B→evXc)<6.5% at the 90% confidence level. This corresponds to an upper limit |Vub/Vcb|<0.21.

Determination of

AbstractUsing the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widthsГee of the Υ(1S) and Υ(2S) resonances. We find

) of the

\Gamma _{ee} (\Upsilon (1S)) = 1.34 \pm 0.03 \pm 0.06keV

(1s) and

and

(2s) Resonances and Measurement of R at

\Gamma _{ee} (\Upsilon (2S)) = 0.56 \pm 0.04 \pm 0.02keV.

.39-{GeV}

The effect onГee of applying different prescriptions for radiative corrections is discussed. We also measureR, the ratio of non-resonant hadronic cross section to the Born cross section of μ pair production, at c.m. energyW=9.39 GeV to beR=3.48±0.04±0.16.