Minimalist Seesaw-Scotogenic Mechanism as a Source for Neutrino Physics

Abstract

We identify the smallest discrete flavor symmetry and minimal field content that can simultaneously account for neutrino masses and the dark sector in the context of the discrete dark matter. Minimality is achieved with a $D_4$ symmetry by adding three right-handed neutrinos and three scalar doublets. Within this framework, tree-level and one-loop contributions yield the observed solar--atmospheric mass splitings as well as the observed neutrino mixings. Furthermore, by including CP-violating phases, the model successfully accommodates both normal and inverted ordering. Spontaneous $D_4$ breaking leaves a residual $\mathbb{Z}_2$ symmetry that stabilizes the dark matter candidate, with a predicted mass within the $50$--$200$ GeV range, consistent with LUX-ZEPLIN limits.