2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42481The effective Lagrangian for the seesaw model is derived. Besides the usual dimension-5 operator responsible for light neutrino masses, a dimension-6 operator is included which, for three or less heavy neutrino generations, provides a generic link between low-energy observables and all physical parameters of the high-energy seesaw Lagrangian. Leptogenesis can be then confirmed or ruled out through the measurement of neutrino masses and mixings and the exotic neutrino couplings originated from the dimension-6 operator.6 pages. Based on the talk given at the XXXVIII Rencontres de Moriond (Electroweak Session)High Energy Physics - Phenomenologytext