Do neutrino flavor oscillations forbid large lepton asymmetry of the universe ?

Abstract

It is shown that hypothetical neutrino-majoron coupling can suppress neutrino flavor oscillations in the early universe, in contrast to the usual weak interaction case. This reopens a window for a noticeable cosmological lepton asymmetry which is forbidden for the large mixing angle solution in the case of standard interactions of neutrinos.Comment: 23pages, 7 figures, the version accepted to Nuclear Physics B; a few explanatory comments and one reference are adde