The production of prompt muons ine+e− annihilation has been studied at centre of mass energies near 34.5 GeV. The measured semi-muonic branching ratios ofb andc quarks areB(b»Xμv) =0.117±0.028±0.01 andB(c→Xμv)=0.082 ±0.012a−0.01+0.02. The fragmentation functions of heavy quarks are hard, <zb>=0.85a−0.12–0.07+0.10+0.02 and <zc> =0.77a−0.07–0.11+0.05+0.03. Limits have been set on flavour changing neutral current decays:B(b→Xµ+µ−) <0.02 andB(b→Xµ+µ− (95% confidence level).
THE VALUE OF ASYMMETRY WAS DETERMINED USING A SAMPLE OF PROMPT MUONS.
The production of electrons by bottom and charm hadrons has been studied in e + e − annihilation at 34.6 GeV center of mass energy. It is observed that the b quark fragmentation function is peaked at large values of the scaling variable z with 〈 z b 〉 = 0.84 +0.15 + 0.15 −0.10 − 0.11 . For c quarks 〈 z c 〉 = 0.57 +0.10 + 0.05 −0.09 − 0.06 is observed. A forward-backward charge asymmetry of A = −0.25 ± 0.22 was measured in b production.
THE VALUE OF ASYMMETRY WAS DETERMINED USING A SAMPLE OF PROMPT ELECTRONS.
THE VALUE OF ASYMMETRY WAS DETERMINED USING A SAMPLE OF PROMPT ELECTRONS.
The forward-backward charge asymmetry for the process e + e − → b b ̄ → μ ± + hadrons has been measured using the JADE detector at PETRA. An asymmetry of (−22.8 ± 6.0 ± 2.5)% was observed at an average center of mass energy of 34.6 GeV. For comparison, an asymmetry of −25.2% is expected on the basis of the standard Glashow-Salam-Weinberg model.
THE VALUE OF CONST HAVE BEEN RESCALED TO DEFINITION I3(Q) = 1/2 BY OPY.
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We present a comparison of the strong couplings of light ($u$, $d$, and $s$), $c$, and $b$ quarks determined from multijet rates in flavor-tagged samples of hadronic $Z~0$ decays recorded with the SLC Large Detector at the SLAC Linear Collider. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, $c$, and $b$ quarks was made using the SLD precision tracking system. We find: $\alpha_s{_{\vphantom{y}}}~{uds}/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 0.987 \pm 0.027({\rm stat}) \pm 0.022({\rm syst}) \pm 0.022({\rm theory})$, $\alpha_s{_{\vphantom{y}}}~c/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 1.012 \pm 0.104 \pm 0.102 \pm 0.096$, and $\alpha_s{_{\vphantom{y}}}~b/{\alpha_s{_{\vphantom{y}}}~{\rm all}} = 1.026 \pm 0.041 \pm 0.041\pm 0.030.$
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We have studied the production of D*± mesons in a sample of 1.25 million multihadronic decays of the Z0, in which 1969 candidates have been identified. We have determined the total multiplicity of charged D* mesons in multihadronic Z0 decays to be
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Multiplicity data uncorrected for decay branching ratios.
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Using about 950000 hadronic events collected during 1991 and 1992 with the ALEPH detector, the ratios r b = α s b α s udsc and r uds = α s uds α s cb have been measured in order to test the flavour independence of the strong coupling constant α s . The analysis is based on event-shape variables using the full hadronic sample, two b -quark samples enriched by lepton tagging and lifetime tagging, and a light-quark sample enriched by lifetime antitagging. The combined results are r b = 1.002±0.023 and r uds = 0.971 ± 0.023.
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Charged conjugate state is assumed.
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The forward-backward asymmetry in e + e − → b b at s = 57.9 GeV and the b-quark branching ratio to muons have been measured using neural networks. Unlike previous methods for measuring the b b forward-backward asymmetry where the estimated background from c -quark decays and other sources are subtracted, here events are categorized as either b b or non- b b events by neural networks based on event-by-event characteristics. The determined asymmetry is −0.429 ± 0.044 (stat) ± 0.047 (sys) and is consistent with the prediction of the standard model. The measured B B mixing parameter is 0.136 ± 0.037 (stat) ± 0.040 (sys) ± 0.002 (model) and the measured b-quark branching ratio to muons is 0.122 ± 0.006 (stat) ± 0.007 (sys).
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