Using the CLEO III detector, we measure absolute cross sections for e+e- --> hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. The values of R, the ratio of hadronic and muon pair production cross sections, are determined within 2% total r.m.s. uncertainty.
Measured values of R as a function of CM energy. The first DSYS error is the correlated uncertainty and the second is the uncorrelated.
We have measured theR value in non-resonante+e− annihilation using the ARGUS detector at the storage ring DORIS II. At a centre-of-mass energy\(\sqrt s= 9.36\) GeV the ratio of the hadronic cross-section to the μ-pair cross section in lowest order QED has been determined to beR=3.46±0.03±0.13. In addition, we have measured the charged-particle multiplicities in non-resonant hadron production at\(\sqrt s= 10.47\) GeV just below theB\(\bar B\) threshold and in ϒ (4S) resonance decays. For the average charged-particle multiplicities in continuum events and ϒ(4S)→B\(\bar B\) decays we obtain <n>cont=8.35±0.02±0.20 and <n>ϒ(4s)=10.81±0.05±0.23.
Corrected for radiative effects and acceptance.
Unfolded charged particle multiplicity distribution for continuum events.
Unfolded charged particle multiplicity distribution for UPSILON(4S) events.
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Data from Run 1. There is an additional overall systematic uncertainty of 5.2 pct.
Data from Run 2. There is an additional overall systematic uncertainty of 5.2 pct.
Average R value.
Using the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widthsГeeof the Υ(1S) and Υ(2S) reson
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NUMBER OF K0S PER EVENT IN THE UPSILON REGION.
NUMBER OF ANTI(LAMBDA)S PER EVENT IN THE UPSILON REGION. FOR UPSI(4S) RESULTS SEE 'A'.
DSIG/DP DISTRIBUTIONS FOR K0 AND (ANTI) LAMBDA PRODUCTION AT THE UPSILON RESONANCES.
The branching fraction for the decay of the ϒ(1S) into τ paris has been measured to be (3.4±0.4±0.4)%. This result agrees with the previously measured branching ratio of the decay into muon pairs.
VISIBLE CROSS SECTIONS IN THE PEAK.
No description provided.
Using the CLEO detector at the Cornell Electron Storage Ring, the authors have measured the leptonic branching fractions, Bμμ, of the ϒ(1S), ϒ(2S), and ϒ(3S) to be 2.7±0.3±0.3%, 1.9±1.3±0.5%, and 3.3±1.3±0.7%, respectively. Combining these values of Bμμ with previous measurements of the leptonic widths of these resonances, the authors find the total widths of the ϒ(1S), ϒ(2S), and ϒ(3S) to be 48±4±4, 27±17±6, and 13±4±3 keV.
No description provided.
The rationR=σ(e+e−→hadrons)/σ(e+e−→ µ+ µ−) was measured with the LENA detector at DORIS in a scan between 7.40 and 7.48 GeV and between 8.67 and 9.43 GeV center of mass energies. Corrected for QED radiative effects,R is found to be constant with an average value ofR=3.37 ±0.06stat±0.23syst. No narrow resonances withΓee(Γhad/Γtot)⊗0.30 keV (95% C.L.) and no steps have been observed. Based on this value ofR, revised values for υ(1S) resonance parameters are presented.
No description provided.
No description provided.
NUMERICAL VALUES GIVEN IN APPENDIX IN PREPRINT. STATISTICAL ERRORS ONLY.
The reaction e + e − → hadrons has been measured in the ϒ and ϒ′ region using the DASP detector at the DESY storage ring DORIS. The following final results are obtained: R had (9.5 GeV)=3.73±0.16±0.28, Γ ee ( ϒ )=(1.23 ± 0.08 ± 0.12) keV, B μμ ( ϒ )=(3.2±1.3±0.3)%, Γ ee Γ had Γ tot (ϒ′)=(0.55±0.11 ±0.06) keV , and M ( ϒ ′)− M ( ϒ )=(556 ±10) MeV.
CROSS SECTION AROUND UPSILON AND UPSILON PRIME.
No description provided.
We have measured the inclusive cross section for η production in e+e− interactions near charm threshold using the Crystal Ball detector. No pronounced structure in the energy dependence is observed. By comparing cross sections above and below charm threshold we obtain the limits (90% confidence limit): R(e+e−→FF¯X)RB(F→ηx)<0.15−0.32 (for Ec.m. from 4.0 to 4.5 GeV), RB(D→ηx)<0.13. Our results are inconsistent with a previous report of a large energy dependence of the η cross section ascribed to the crossing of the FF* and F*F* production thresholds.
Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
THE 4.028 GEV DATA ARE NOT INCLUDED IN THE 4.005-4.082 GEV BIN. Axis error includes +- 0.0/0.0 contribution (?////DECAY PI0 --> 2GAMMA//RES-DEF(RES=ETA,BACK=CORRECTED,DEF=340 < M( 2GAMMA ) < 800 MEV)//DECAY-BR(BRN=ETA --> 2GAMMA,BR=38 PCT)).
AT FIXED ENERGIES.