First results from the magnetic detector PLUTO at the new e + e − storage ring PETRA are shown. The ratio R of the cross section for hadron production to that for μ-pair production has been measured to be R = 5.0 ± 0.5 at 13 GeV and 4.3 ±0.5 at 17 GeV. Both values have an additional systematic error of 20%. The events show a typical 2-jet structure. The mean transverse momentum approaches a constant value with increasing energy implying a shrinkage of the jet opening angle.
TAU HEAVY LEPTON PAIR CONTRIBUTIONS HAVE BEEN SUBTRACTED. R AT 13 AND 17 GEV, TOGETHER WITH SOME SELECTED LOWER ENERGY MEASUREMENTS FROM PLUTO AT DORIS.
Data from earlier preprint DESY-79-06. NUMERICAL VALUES MEASURED OFF GRAPH IN PREPRINT.
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.
The contributions of the PLUTO experiment to e + e − physics at collision energies in the range of 3–32 GeV are reviewed. The review briefly sketches the storage rings DORIS and PETRA at DESY, and describes the most important features of the PLUTO detector, of data processing, and of the analysis methods. It covers the physics results in the fields of electroweak interactions, of the heavy lepton τ and the search for still heavier leptons, of hadron production with evidence for quark and gluon jets, as well as for single and multiple gluon emission, of Y decays and their relation to QCD, and presents results in high-energy photon-photon interactions, including the first measurement of the photon structure function.
SUMMARY OF MEASUREMENTS OF R (REVISED FROM EARLIER PUBLICATIONS). RADIATIVE CORRECTIONS APPLIED. TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED.
Summary of measurements of the cross section around the UPSI(1S) (revised from earlier publication Phys.Lett. 76B (1978) 243) with radiative corrections a pplied and leptons contribution subtracted. Data extracted from graph by VVE.
Measurements of energy-energy correlations in hadronic final states produced in e + e − annihilation at c.m. energies between 7.7 and 31.6 GeV are presented. The data are compared to perturbative QCD predictions. Good qualitative agreement above 20 GeV c.m. energy is found. The importance of non-perturbative effects is discussed, as well as the detailed behaviour of the correlation near 180°.
No description provided.
OPPOSITE SIDE ENERGY-ENERGY CORRELATIONS NEAR 180 DEG.
ENERGY-ENERGY CORRELATION INTEGRATED IN THE REGION 60 TO 120 DEG.
Using the DASP detector at the DESY storage ring DORIS we have continued measuring e + e − annihilations near and on the ϒ(9.46) resonance. From the cross sections for e + e − → μ + μ − and e + e − → hadrons we obtain a μ + μ − branching ratio for the ϒ(9.46) of (2.9 ± 1.3 ± 0.5) %, a leptonic width г ee = (1.35 ± 0.11 ± 0.22) keV and a total width of (47 −15 +37 keV.
VISIBLE HADRONIC CROSS SECTION. PEAK VALUE AT UPSILON IS 10.1 +- 0.7 NB.
No description provided.
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.
None
No description provided.
None
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.
Transverse particle momenta have been measured ine+e− annihilation into hadrons at c.m. energies between 9.4 and 31.6 GeV. The data are fully corrected for detector effects and radiation in the initial state. A comparison is made with recent QCD calculations.
MEASUREMENTS MADE WITH RESPECT TO THE SPHERICITY AXIS.
MEASUREMENTS MADE WITH RESPECT TO THE THRUST AXIS.
MEASUREMENTS MADE WITH RESPECT TO THE MOST ENERGETIC PARTON AXIS.