F. Selonke

Branching ratio and mass spectrum of the decay ϒ′ → ϒπ+π−

Abstract The reaction e + e − → ϒ ′ → ϒπ + π − , with ϒ → anything, has been measured using the ARGUS detector at DORIS . We obtain a mass difference M ( ϒ ′) − M ( ϒ ) = (562 ± 3) MeV and a decay branching ratio BR( ϒ ′→ ϒπ + π − )=(17.9±0.9±2.1)%. The invariant mass spectrum of the π + π − system differs from phase space, but is well described by a matrix element of the form ( M ππ 2 − λM π 2 ) with λ =2.6±0.5. We also report preliminary results on the exclusive decay ϒ′ → ϒπ + π − , with ϒ → e + e − , and obtain BR( ϒ → e + e − ) = (2.8 ± 0.4 ± 04±0.3)%.

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.

Production and Decay of the F Meson in

Abstract Using the ARGUS detector at DORIS we have observed the prediction of the charged D ∗ meson in e + e − annihilation at a center of mass energy of 10 GeV. The D ∗ fragmentation function has been measured using the decay channels D ∗+ → D 0 π + and D 0 → K − π + and K − π + π + π − . We find σ·Br for the channels D 0 → K − π + and D 0 → K − π + π + π − to be (23.6 ± 2.2 ± 4.7) pb and (51.0 ± 4.6 ± 15.5) pb respectively, and the ratio of branching ratios Br(D 0 → K − π + π + π − )/Br(D 0 → K − π + ) = 2.17 ± 0.28 ± 0.23. In addition we measure the mass difference M( D ∗+ ) − M( D 0 ) to be (145.46 ± 0.07 ± 0.03) MeV, and set an upper limit for D 0 − D 0 mixing of 0.11.

e^+ e^-

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

Determination ofГ ee of the Υ(1S) and Υ(2S) resonances, and measurement ofR atW=9.39 GeV

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

\gamma (e e

and

\Upsilon

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