KeV dark matter in minimal extended seesaw model and its predictions in neutrinoless double beta decay and baryogenesis

Abstract

We develop an $A_4\times Z_4\times Z_2$ symmetry extension of Standard Model under the minimal extended seesaw (MES) mechanism which successfully predicts neutrino masses and mixings patterns. This model breaks $\mu -\tau$ symmetry of neutrino mass matrix and explains leptonic mixing with non-zero ${\theta }_{13}$. We study the phenomenological results of the keV-scale sterile neutrino as a dark matter candidate along with other phenomenologies such as neutrino oscillation observables, neutrinoless double beta decay, baryogenesis via leptogenesis, etc. Dirac CP-violating phase ${\delta }_{CP}$ and two Majorana phases $\alpha$ and $\beta$ are also calculated from the leptonic mixing matrix. Best-fit values of the model parameters and neutrino observables are calculated from ${\chi }^2$ analysis. The model predicts best-fit values of neutrino mixing angles to be ${\sin }^2{\theta }_{23}=0.555,{\sin }^2{\theta }_{12}=0.301$ and ${\sin }^2{\theta }_{13}=0.022$ for normal hierarchy. Significant results consistent with experimental data are also observed for effective neutrino mass $m_{\beta \beta }\sim (0.97-5.02)$ meV, effective electron mass $m_{\beta }\sim (0.084-0.41)$eV and sum of active neutrino masses $\sum m_i<0.12$ eV. The model does not favour Inverted hierarchy at the 3$\sigma$ level with the given parameter space.

Comments: 27 pages, 10 Figures