Dirac neutrino mass generation from dark matter

TL;DR

This paper introduces a minimal model where Dirac neutrino masses are generated radiatively through dark matter interactions, expanding on previous Majorana-based models and exploring dark matter candidates and neutrino mixing.

Contribution

It proposes a novel minimal model for Dirac neutrino mass generation via a radiative mechanism involving dark matter, including potential dark matter candidates and neutrino mixing.

Findings

Lightest Dirac fermion can serve as dark matter candidate.

Model accommodates realistic neutrino mixing with A4 symmetry.

Different parameter space regions yield viable dark matter candidates.

Abstract

In 2006, a simple extension of the Standard Model was proposed in which neutrinos obtain radiative Majorana masses at one-loop level from their couplings with dark matter, hence the term "scotogenic," from the Greek "scotos" meaning darkness. Here an analogous mechanism for Dirac neutrino masses is discussed in a minimal model. In different ranges of the parameter space, various candidates for dark matter are possible. In particular, the lightest Dirac fermion which appears in the loop diagram generating neutrino mass can be a viable dark matter candidate. Such a possibility does not exist for the Majorana case. Realistic neutrino mixing in the context of $A_4$ is discussed. A possible supersymmetric extension is also briefly discussed.