Seesaw roadmap to neutrino mass and dark matter

TL;DR

This paper explores various theoretical pathways to generate neutrino masses, both Majorana and Dirac types, through generalized operators, and links the symmetries ensuring neutrino nature to dark matter stability.

Contribution

It introduces new field contraction possibilities involving scalars beyond the Standard Model Higgs and connects symmetries for Dirac neutrinos to dark matter stability.

Findings

Multiple pathways for neutrino mass generation are identified.

New scalar contractions expand the model-building landscape.

Symmetries for Dirac neutrinos can also stabilize dark matter.

Abstract

We describe the many pathways to generate Majorana and Dirac neutrino mass through generalized dimension-5 operators a la Weinberg. The presence of new scalars beyond the Standard Model Higgs doublet implies new possible field contractions, which are required in the case of Dirac neutrinos. We also notice that, in the Dirac neutrino case, the extra symmetries needed to ensure the Dirac nature of neutrinos can also be made responsible for stability of dark matter.