Vanishing effective Majorana neutrino mass and light sterile neutrinos

Abstract

We examine the possibility of vanishing effective Majorana mass [Formula: see text] in the presence of one or two sterile neutrinos taking into account the recent data on neutrino masses and mixings, particularly, on [Formula: see text]. Also, within the framework of standard three active neutrinos, we find that effective Majorana mass [Formula: see text] can be vanishingly small if neutrino masses observe normal hierarchy. However, the same is not valid for inverted hierarchical neutrino masses. The predictions for Majorana phases [Formula: see text] and [Formula: see text] have also been obtained and shown as scatter plots. We also examine the condition [Formula: see text] within the framework wherein fermion sector has been extended by the addition of either one or two sterile neutrinos. The condition of vanishing effective Majorana mass is found to be inconsistent with the recent measurement of [Formula: see text] in these classes of models except for [Formula: see text], [Formula: see text] neutrino mass scheme for small values of the lightest neutrino mass, [Formula: see text].