Neutrino masses and mixing from milli-charged dark matter

Abstract

We propose a simple extension to the Standard Model, wherein neutrinos naturally attain small Majorana masses through a one-loop radiative mechanism featuring particles within the loops characterized by milli-charges. Unlike the conventional scotogenic model, our approach avoids imposing a discrete symmetry or expanding the gauge sector. The minuscule electric charges ensure the stability of the lightest particle within the loop as a viable dark matter candidate. We systematically investigate for both, dark matter freeze-in and freeze-out, the far-reaching phenomenological implications arising from these minuscule charges.