2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/188400We investigate a flavored washout effect due to the decay of the lightest right-handed neutrino, assuming that there is non-vanishing initial lepton asymmetry and the decay of the lightest right-handed neutrinos gives negligible contribution to the asymmetry. We figure out general features of the washout effect. It is shown that there is a novel parameter region where an effect that is negligible in most cases plays a critical role and a sizable lepton asymmetry can survive against the washout process even in a strong washout region.14 pages, 7 figuresHigh Energy Physics - Phenomenologytext