We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The observables are obtained to high jet resolution scales with the JADE, Durham, Cambridge and cone jet finders, and compared with the predictions of various QCD and Monte Carlo models. The strong coupling strength, alpha_s, is determined at each energy by fits of O(alpha_s^2) calculations, as well as matched O(alpha_s^2) and NLLA predictions, to the data. Matching schemes are compared, and the dependence of the results on the choice of the renormalization scale is investigated. The combination of the results using matched predictions gives alpha_s(MZ)=0.1187+{0.0034}-{0.0019}. The strong coupling is also obtained, at lower precision, from O(alpha_s^2) fits of the c.m.s. energy evolution of some of the observables. A qualitative comparison is made between the data and a recent MLLA prediction for mean jet multiplicities.
Overall result for ALPHAS at the Z0 mass from the combination of the ln R-matching results from the observables evolved using a three-loop running expression. The errors shown are total errors and contain all the statistics and systematics.
Weighted mean for ALPHAS at the Z0 mass determined from the energy evolutions of the mean values of the 2-jet cross sections obtained with the JADE and DURHAMschemes and the 3-jet fraction for the JADE, DURHAM and CAMBRIDGE schemes evaluted at a fixed YCUT.. The errors shown are total errors and contain all the statistics and systematics.
Combined results for ALPHA_S from fits of matched predicitions. The first systematic (DSYS) error is the experimental systematic, the second DSYS error isthe hadronization systematic and the third is the QCD scale error. The values of ALPHAS evolved to the Z0 mass using a three-loop evolution are also given.
Topological distributions of hadrons from the reaction e + e − → hadrons are studied at center of mass energies of about 33 GeV. The experimental distributions in the parameters acoplanarity and tripodity, both sensitive to events with a four-jet structure, show significant deviations from the expectations for two- and three-jet events. They can be described well by the inclusion of four-jet events. The relative magnitude of the observed effect indicates second order QCD as its probable origin.
No description provided.
The reaction e + e - → e + e - η' has been observed in the JADE experiment at PETRA, by detecting the final state π + π - γ, resulting from the decay η' → γϱ 0 . The cross section was measured at an average beam energy of 17.15 GeV to be σ(e + e - → e + e - η') = 2.2 ± 0.2 (stat.) ± 0.4(syst.) nb, yielding the radiative width Γ η'γγ = 5.0 ± 0.5(stat.) ± 0.9 (syst.) keV.
No description provided.
The angular distribution and the s dependence of the total cross section for the process e + e − → μ + μ − have been measured using the JADE detector at PETRA. After radiative corrections, a forward-backward asymmetry of −(11.8±3.8) % was observed at an average centre of mass energy of 33.5 GeV. For comparison, an asymmetry of −7.8 % is expected on the basis of the standard Glashow-Salam-Weinberg model.
Best fit to total cross section in energy range.
ANGULAR DISTRIBUTION.
Forward-backward asymmetry within the acceptnce region.
Data on p and Λ production by e + e − -annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon-antibaryon pairs is seen.
No description provided.
No description provided.
AVERAGE NUMBER OF ANTIBARYONS PER HADRONIC EVENT. AN EXPONENTIAL SLOPE OF 2.5 GEV*-1 IN E WAS ASSUMED IN EXTRAPOLATING E*D3(SIG)/DP**3 TO ALL MOMENTA.
Data on hadron production by e + e − annihilation at c.m. energies between 12 and 36.6 GeV have been collected using the JADE detector. They have been analysed in terms of single-photon and weak neutral-current exchange assuming production of quark-antiquark pairs with only d, u, s, c and b quarks to produce values for the quark weak neutral-current couplings. A further analysis in terms of the Glashow-Salam-Weinberg theory produced the result, sin 2 θ W = 0.22 ± 0.08 . The theory has therefore been tested in a new energy domain and within the context of the neutral weak couplings of the first, second and third generation quarks.
No description provided.
WIDTH(Z) = 2.5 GEV WAS ASSUMED. CONST(N=SIN2TW) WAS DETERMINED FROM RATIO(HADRONS/MU). FIRST ORDER QCD.
A search for narrow resonances in e + e − annihilation between 33.00 and 36.72 GeV is reported. No evidence is found for the existence of such states. The 90% confidence upper limit on the integrated resonance cross section is determined to be 28 nb MeV, a value significantly below that expected for the lowest t t bound state.
AVERAGE R VALUE THROUGHOUT ENERGY RANGE. SYSTEMATIC ERROR IS CONSERVATIVE AND WILL BE IMPROVED.
R VALUES AT 20 MEV STEPS. DATA TAKEN FROM TABLE IN THE PREPRINT.
The processes e + e − → e + e − and μ + μ − have been studied at PETRA using the JADE detector. The data, which were collected at s -values of up to 1300 GeV 2 have been analysed in terms of an electro-weak extension of QED to obtain values for the weak vector and axial vector couplings in the lepton sector. The values obtained agree with the predictions of the standard Salam-Weinberg model and the data are further analysed in terms of this model to obtain the limits 0.10 < sin 2 ϑ w < 0.40 (68% CL). The mass of the neutral weak gauge boson is deduced to be greater than 51 GeV/ c 2 .
No description provided.
No description provided.
No description provided.
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