2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/109916We revisit Sakurai's remark on the regularities of lepton-pair widths for mesons, extending the panorama to radiative $X \to γγ$ and total decays. The regularities persist, and somehow surprisingly some of them seem to relate with Fermi's constant -or $Z^0$-.6 pages, 2 figuresHigh Energy Physics - Phenomenologytext