Neutrino masses, cosmological bound and four zero Yukawa textures

Abstract

Four zero neutrino Yukawa textures in a specied weak basis, combined with μτ symmetry and type-I seesaw, yield a highly constrained and predictive scheme. Two alternately viable 3 × 3 light neutrino Majorana mass matrices m_νA=m_νB result with inverted/normal mass ordering. Neutrino masses, Majorana in character and predicted within definite ranges with laboratory and cosmological inputs, will have their sum probed cosmologically. The rate for 0νββ decay, though generally below the reach of planned experiments, could approach it in some parameter region. Departure from μτ symmetry due to RG evolution from a high scale and consequent CP violation, with a Jarlskog invariant whose magnitude could almost reach 6 × 10^-3, are explored.