The recent measurements of the Michel parameters in tau decays enable, for the first time, a thorough analysis of the leptonic sector. In general, in models beyond the Standard Model, these parameters will be altered through changes in the W and Z couplings, and/or through interactions mediated by new gauge bosons. We perform a complete, model independent analysis of the constraints imposed by the present data on such boson-mediated interactions, and point out the existence of useful relations among the couplings.
@article{arxiv.hep-ph/9505327,
title = {Constraining new interactions with leptonic tau decays},
author = {A. Pich and J. P. Silva},
journal= {arXiv preprint arXiv:hep-ph/9505327},
year = {2009}
}