2018 Impact factor 4.843
Particles and Fields

Eur. Phys. J. C 16, 229-252
DOI 10.1007/s100520000402

## A study of the Lorentz structure in tau decays

The DELPHI Collaboration

P.Abreu22 et al.

22 LIP, IST, FCUL - Av. Elias Garcia, 14-1o, 1000 Lisboa Codex, Portugal

Received: 14 February 2000 / Revised version: 7 March 2000 /
Published online: 8 May 2000 - © Springer-Verlag 2000

Abstract
This paper describes a measurement of the Michel parameters, , , , , and the average helicity, , in lepton decays together with the first measurement of the tensor coupling in the weak charged current. The pairs were produced at the LEP e+ e-collider at CERN from 1992 through 1995 in the DELPHI detector. Assuming lepton universality in the decays of the the measured values of the parameters were: , , , , . The strength of the tensor coupling was measured to be . The first error is statistical and the second error is systematic in all cases. The results are consistent with the structure of the weak charged current in decays of the lepton.

Copyright Società Italiana di Fisica, Springer-Verlag 2000