Neutrino Masses and Mixings and Phenomenological Study of eV-Scale Sterile Neutrino

In this work, we study the phenomenological effects of an eV-scale sterile neutrino in neutrinoless double beta decay and active neutrino masses and mixings. We use \(A_4\times Z_3\) discrete symmetry extension of Standard Model to develop a new model of neutrino masses and mixings in 3+1 scheme within the Minimal Extended Seesaw(MES) mechanism. We consider an \(A_4\) triplet right-handed neutrino \(\nu _R\) and one eV-scale sterile neutrino singlet S in which the deviation from \(\mu -\tau \) symmetry in the active neutrino mass matrix is generated through an antisymmetric interaction of \(\nu _R\) This model successfully explains leptonic mixing with non-zero \(\theta _{13}\) and the Planck cosmological bound on sum of active neutrino mass \(\sum m_i < 0.12\) eV is satisfied. The effects of S on \(m_{\beta }\) and \(m_{\beta \beta }\) are also studied and significant results are observed within the experimental bounds.