Scotogenic U(1)χ Dirac neutrinos

Ernest Ma

doi:10.1016/j.physletb.2019.05.006

Abstract

The standard model of quarks and leptons is extended to include the gauge symmetry U(1)χ which comes from SO(10)→SU(5)×U(1)χ. The radiative generation of Dirac neutrino masses through dark matter is discussed in two examples. One allows for light Dirac fermion dark matter. The other allows for self-interacting scalar dark matter with a light scalar mediator which decays only to two neutrinos.

Highlights

Whereas neutrinos are usually assumed to be Majorana, there is yet no experimental evidence, i.e. no definitive measurement of a nonzero neutrinoless double beta decay
To make a case for neutrinos to be Dirac, the first is to justify the existence of a right-handed neutrino νR, which is not necessary in the standard model (SM) of quarks and leptons
Whereas the original idea [8] was applied to Majorana neutrinos, one-loop [9, 10] and two-loop [11] examples for Dirac neutrinos already exist in the context of the SM

Summary

Introduction

Whereas neutrinos are usually assumed to be Majorana, there is yet no experimental evidence, i.e. no definitive measurement of a nonzero neutrinoless double beta decay. To make a case for neutrinos to be Dirac, the first is to justify the existence of a right-handed neutrino νR, which is not necessary in the standard model (SM) of quarks and leptons. New insights into dark matter [3, 4] and Dirac neutrino masses [5] have emerged. For a generic discussion of Dirac neutrinos, see Ref.

Results

Conclusion