Measurement of the Michel Parameters in Leptonic Tau Decays

Abstract

The Michel parameters of the leptonic tau decays are measured using the OPAL detector at LEP. The Michel parameters are extracted from the energy spectra of the charged decay leptons and from their energy-energy correlations. A new method involving a global likelihood fit of Monte Carlo generated events with complete detector simulation and background treatment has been applied to the data recorded at center-of-mass energies close to sqrt(s) = M(Z) corresponding to an integrated luminosity of 155 pb-1 during the years 1990 to 1995. If e-mu universality is assumed and inferring the tau polarization from neutral current data, the measured Michel parameters are extracted. Limits on non-standard coupling constants and on the masses of new gauge bosons are obtained. The results are in agreement with the V-A prediction of the Standard Model.

arXiv comment32 pages, LaTeX, 9 eps figures included, submitted to the European Physical Journal C

Cited by in corpus (7)

• Strong Dynamics and Electroweak Symmetry Breaking
• Search for lepton-flavor-violating tau-lepton decays to $\ell \gamma$ at Belle
• Michel parameters in radiative muon decay
• Michel parameters in the presence of massive Dirac and Majorana neutrinos
• Dissipative effects in semileptonic B decays
• Complementary bound on $W^{\prime }$ mass from Higgs to diphoton decay
• Effects of charged Higgs bosons in the deep inelastic process ν_τ {\cal N} \to τ^- X and the possibility of detecting tau-neutrinos at cosmic neutrino detectors