The ration R = σ (e + e − → hadrons) σ μμ was measured between 12.0 and 36.7 GeV c.m. energy W with a precision of typically ± 5.2%. R is found to be constant with an average R = 4.01 ± 0.03 (stat) ± (syst.) for W ⩾ 14 GeV. Quarks are found to be point-like, the mass parameter describing a possible quark form-factor being larger than 186 GeV. Fits including QCD corrections and a weak neutral-current contribution are presented.
DATA OF RUNPERIOD 1.
DATA OF RUNPERIOD 2.
R MEASURED IN SCANNING MODE.
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.
Measurements of the charged multiplicities for hadron production in e + e − annihilation in the center of mass energy range 9–32 GeV have been made. The average charged multiplicity has an energy dependence much stronger than ln s and similar to that reported for pp collisions. Quantitative differences are observed in the magnitude of both the average multiplicity 〈 n ch 〉 and the dispersion D ch for e + e − and pp interactions at the same center of mass energy. 〈 n ch 〉 and the ratio 〈 n ch / D ch in e + e − annihilations are significantly larger than in pp collisions and are found to be in overall agreement with QCD predictions. KNO scaling is seen to be satisfied.
THE FINAL TABLE ENTRY COMBINES THE DATA FROM THE THREE HIGHEST ENERGY BINS.
This report reviews the experimental investigation of high energy e + e − interactions by the MARK J collaboration at PETRA, the electron-positron colliding beam accelerator at DESY in Hamburg, Germany. The physics objectives include studies of several purely electromagnetic processes and hadronic final states, which further our knowledge of the nature of the fundamental constituents and of their strong, electromagnetic and weak interactions. Before discussing the physics results, the main features and the principal components of the MARK J detector are discussed in terms of design, function, and performance. Several aspects of the on-line data collection and the off-line analysis are also outlined. Results are presented on tests of quantum electrodynamics using e + e − → e + e − , μ + μ − and τ + τ − , on the measurement of R , the ratio of the hadronic to the point-like muon pair cross section, on the search for new quark flavors, on the discovery of three jet events arising from the radiation of hard noncollinear gluons as predicted by quantum chromodynamics, and on the determination of the strong coupling constant α s .
SUMMARY OF RESULTS FOR R FROM TOTAL OF 2595 HADRON EVENTS. INCLUDES RED = 1046, 1079, 1072 AND 1114.
MEAN THRUST AND THRUST DISTRIBUTION (1/N)*DN/DTHRUST AT 13, 17, 22 AND 30 GEV. SOMEWHAT DETECTOR DEPENDENT. INCLUDES RED = 1079 AND 1072. SEE ALSO RED = 1114. ALSO JET ANALYSIS USING FOX-WOLFRAM MOMENTS.
OBLATENESS DISTRIBUTION AT 17 AND 27.4 TO 31.6 GEV. SEE RED = 1146.
Hadron production by e + e − annihilation has been studied for c.m. energies W between 13 and 31.6 GeV. As a function of 1n W the charged particle multiplicity grows faster at high energy than at lower energies. This is correlated with a rise in the plateau of the rapidity distribution. The cross section s d σ /d x is found to scale within ±30% for x > 0.2 and 5 ⩽ W ⩽ 31.6 GeV.
CHARGED PARTICLE MULTIPLICITIES.
RAPIDITY DISTRIBUTION.
RAPIDITY DISTRIBUTION.
Measurements ofR, sphericity and thrust are presented for c.m. energies between 12 and 31.6 GeV. A possible contribution of at\(\bar t\) continuum can be ruled out for c.m. energies between 16 and 31 GeV.
No description provided.
None
CORRECTIONS HAVE BEEN APPLIED FOR CONTRIBUTIONS FROM BEAM-GAS SCATTERING, TWO PHOTON SCATTERING, TAU HEAVY LEPTON PAIR PRODUCTION, AND FOR RADIATIVE EFFECTS. THE 13 AND 17 GEV MEASUREMENTS WERE PREVIOUSLY REPORTED IN R. BRANDELIK ET AL., PL 83B, 261 (1979).
PRELIMINARY INCLUSIVE CHARGED PARTICLE DISTRIBUTIONS.
Results on the hadronic final state in e/sup +/e/sup -/ annihilation at 13, 17 and 27.4 GeV are presented. There is no compelling evidence for the existence of the t quark in these data, which are in general agreement with a simple quark parton model. Some tentative indications of QCD effects are observed in the p/sub T//sup 2/ distributions.
TAU HEAVY LEPTON CONTRIBUTION SUBTRACTED.
INCLUSIVE HADRON SPECTRUM. THESE DATA AT 13, 17 AND 27.4 GEV ON S*D(SIG)/DX ARE INCLUDED IN THE RECORD OF R. BRANDELIK ET AL., PL 89B, 418 (1980).
None
No description provided.
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