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Article
Measurement of theZ 0 line shape parameters and the electroweak couplings of charged leptons
We report on an improved measurement of the mass of theZ 0 boson, its total width and its partial decay widths into hadrons and leptons, as well as the effective axial vector and vector couplings to charged lepto...
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Article
A direct measurement of theZ 0 invisible width by single photon counting
The OPAL detector at LEP is used to measure the branching ratio of theZ 0 into invisible particles by measuring the cross section of single photon events ine + e − collisions at centre-of-mass energies near theZ
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Article
Measurement of three-jet distributions sensitive to the gluon spin ine + e − annihilations at \(\sqrt s = 91\) GeV
Three-jet variables constructed from multi-hadronic events produced byZ 0 decays are compared to theoretical calculations assuming a vector gluon or a hypothetical scalar gluon. The data yield conclusive direct e...
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Article
A global determination of \(\alpha _s (M_{Z^0 } )\) at LEP
The value of the strong coupling constant, \(\alpha _s (M_{Z^0 } )\) , is determined from a study of 15 different obs...
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Article
Properties of multihadronic events with a final state photon at \(\sqrt s = M_{Z^0 } \)
The properties of final state photons in multihadronic decays of theZ 0 and those of the recoiling hadronic system are discussed and compared with theoretical expectations. The yield of two and three jet events w...
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Article
A measurement of electron production in hadronicZ 0 decays and a determination of \(\Gamma (Z^0 \to b\bar b)\)
The production rate of electrons with momentump>4 GeV/c and large momentum transverse to the jet containing the electron has been measured in 136000 hadronic decays of theZ 0 recorded with the OPAL detector at LE...
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Article
Inclusive neutral vector meson production in hadronicZ 0 decays
Results are reported of a study of neutral vector meson production in multihadronicZ 0 decays in the OPAL experiment at LEP. Pions and kaons have been identified by specific ionisation energy loss andK ± π ∓ andK
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Article
A study of charged particle multiplicities in hadronic decays of theZ 0
We present an analysis of multiplicity distributions of charged particles produced inZ 0 hadronic decays. The results are based on the analysis of 82941 events collected within 100 MeV of theZ 0 peak energy with ...
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Article
The forward-backward asymmetry of \(e^ + e^ - \to b\bar b and e^ + e^ - \to c\bar c\) using leptons in hadronicZ 0 decays
The forward-backward asymmetries of \(e^ + e^ - \to Z^0 \to b\bar b and e^ + e^ - \to Z^0 \to c\bar c\) have been me...
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Article
A determination ofα s( \(M_{Z^0 } \) ) at LEP using resummed QCD calculations
The strong coupling constant, αs, has been determined in hadronic decays of theZ 0 resonance, using measurements of seven observables relating to global event shapes, energy correlations and jet rates. The data h...
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Article
Precision measurements of the neutral current from hadron and lepton production at LEP
New measurements of the hadronic and leptonic cross sections and of the leptonic forward-backward asymmetries ine + e − collisions are presented. The analysis includes data recorded up to the end of 1991 by the O...
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Article
Measurements of \(B^0 - \bar B^0 \) mixing, \({{\Gamma (Z^0 \to b\bar b)} \mathord{\left/ {\vphantom {{\Gamma (Z^0 \to b\bar b)} {\Gamma (Z^0 \to hadrons)}}} \right. \kern-0em} {\Gamma (Z^0 \to hadrons)}}\) and semileptonic branching ratios forb-flavoured hadrons in hadronicZ 0 decays
From a sample of about 450 000 hadronicZ 0 decays, measurements of the average $$B^0 - \bar B^0 $...
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Article
Measurement of the τ lifetime
The τ lifetime has been measured with the OPAL detector at LEP, from analyses using the impact parameters in decays to single charged tracks, and the decay lengths from τ decays to three charged tracks. The 19...
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Article
QCD coherence studies using two particle azimuthal correlations
From a sample of 146900 hadronicZ 0 decays recorded by the OPAL detector at LEP, we have studied the azimuthal correlations of particles in hadronic events. It is expected that these correlations are sensitive to...
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Article
Measurement of the averageb hadron lifetime inZ 0 decays
A sample of 2610 electron candidates and 2762 muon candidates identified in hadronicZ 0 decays has been used to measure the averageb hadron lifetime. These data were recorded with the OPAL detector during 1990 an...
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Article
A study of differences between quark and gluon jets using vertex tagging of quark jets
Quark and gluon jets with equal energies are identified in three-jet hadronicZ 0 events, using reconstructed secondary vertices from heavy quark decay in conjunction with energy ordering of the jets to anti-tag t...
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Article
A test of the flavour independence of the strong interaction for five flavours
We report on a measurement of the ratio of the strong coupling constants \(\alpha _s (M_{Z^0 } )\) for various data ...
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Article
Studies of strong and electroweak interactions using final state photon emission in hadronicZ 0 decays
The cross section and jet rates ofZ 0 decays into photons and quarks are compared with matrix element Monte Carlos ofO(ααs). Good agreement is found between data and theoretical predictions. From the ratio of eve...
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Article
A measurement ofΓ (Z 0→b \(\Gamma ({\rm Z}^0 \to b\bar b)\) /Γ(Z 0→hadrons) using an impact parameter technique
The fractional partial width of theZ 0 tob quarks, \(\Gamma _{b\bar b} /\Gamma _{had} \) , has been measured by OPAL ...
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Article
A measurement of the forward-backward asymmetry of \(e^ + e^ - \to c\bar c\) and \(e^ + e^ - \to b\bar b\) at centre of mass energies on and near theZ 0 peak usingD *± mesons
A measurement is presented of the forwardbackward asymmetry of the processes \(e^ + e^ + \to c\bar c\) and ...