Measurement of the Michel parameters
in leptonic tau
The OPAL Collaboration
K. Ackerstaff8 - et al.
8 CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland
Received: 25 June 1998 / Published online: 1 March 1999
The Michel parameters of the leptonic decays are measured using the OPAL detector at LEP. The parameters , , (with ) and 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 corresponding to an integrated luminosity of 155 pb-1. If - universality is assumed and inferring the polarization from neutral current data, the measured Michel parameters are: