Dirac Scoto Inverse-Seesaw from $A_4$ Flavor Symmetry

Abstract

We present a Dirac scotogenic-like one loop radiative model where the stability of dark matter is intricately linked to the breaking of $A_4$ flavor symmetry. This breaking induces a $Z_2$ dark symmetry, stabilizing the dark matter candidate. The breaking of $A_4\to Z_2$ leads to cutting the loop and facilitating a "scoto inverse-seesaw" mass mechanism responsible for neutrino mass generation. This elucidates the explicit explanation of two mass-squared differences, $\Delta m_{\mathrm{atm}}^2$ and $\Delta m_{\mathrm{sol}}^2$ observed in neutrino oscillations. Our model accounts for normal and inverted ordering of neutrino masses, revealing sharp correlations between $\sum m_i$ and $⟨m_{\beta }⟩$. It also shows strong compatibility with current data in the ${\delta }_{CP}$-${\theta }_{23}$ plane. Moreover, stringent constraints on scalar masses narrow down the viable dark matter mass regions, accommodating $SU(2{)}_L$ singlet and doublet scalar dark matter as well as fermionic dark matter. Additionally, our model presents a viable avenue for addressing lepton flavor violating decays while remaining consistent with current experimental constraints.

Comments: 35 pages, 16 figures, 2 tables, matches with the published version in JHEP