2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198451The cosmological baryon asymmetry can be explained as remnant of heavy Majorana neutrino decays in the early universe. We study this out-of-equilibrium process by means of Kadanoff-Baym equations which are solved in a perturbative expansion. To leading order the problem is reduced to solving a set of Boltzmann equations for distribution functions.12 pages, 2 figures, typos corrected. To be published in Physics LettersHigh Energy Physics - PhenomenologyAstrophysicsHigh Energy Physics - Theorytext