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Full-Text Articles in Physical Sciences and Mathematics
Test Of The Flavour Independence Of Αs, D. Buskulic, Manoj Thulasidas
Test Of The Flavour Independence Of Αs, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
Using about 950 000 hadronic events collected during 1991 and 1992 with the ALEPH detector, the ratios r b = bs=udsc s and r uds = uds s =cbs have been measured in order to test the avour independence of the strong coupling constant 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.
The Forward-Backward Asymmetry For Charm Quarks At The Z Pole, D. Buskulic, Manoj Thulasidas
The Forward-Backward Asymmetry For Charm Quarks At The Z Pole, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
From 1.4 million hadronic Z decays collected by the ALEPH detector at LEP, an enriched sample of Z → cc̄ events is extracted by requiring the presence of a high momentum D∗±. The charm quark forward-backward charge asymmetry at the Z pole is measured to be AFB0.c = (8.0 ± 2.4) % corresponding to an effective electroweak mixing angle of sin2θWeff = 0.2302 ± 0.0054.
Search For Supersymmetric Particles With R-Parity Violation In Z Decays, D. Buskulic, Manoj Thulasidas
Search For Supersymmetric Particles With R-Parity Violation In Z Decays, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
Searches for supersymmetric particles produced in e+e− interactions at the Z peak have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In a data sample collected by the ALEPH detector at LEP up to 1993, and corresponding to almost two million hadronic Z decays, no signal was observed. As a result, supersymmetric particle masses and couplings are at least as well constrained as under the usual assumption of R-parity conservation.
Michel Parameters And Τ Neutrino Helicity From Decay Correlations In Z → Τ+Τ-, D. Buskulic, Manoj Thulasidas
Michel Parameters And Τ Neutrino Helicity From Decay Correlations In Z → Τ+Τ-, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
No abstract provided.
First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas
First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon production inside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energy z 0:7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function, D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions to D(z) obtained from an O(S ) QCD calculation, the unknown non-perturbative component of D(z) is …