2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214763A complete discussion of the constraints on the Michel parameters and the ambiguities of their interpretation is presented. Estimators of new physics, optimized for a very wide class of hypotheses and models, are proposed.12 pages, Latex, 2 PostScript figuresHigh Energy Physics - Phenomenologytext