Two-loop Dirac neutrino mass and WIMP dark matter

TL;DR

This paper introduces a two-loop scotogenic model linking Dirac neutrino masses with WIMP dark matter, utilizing symmetries to ensure stability and predict observable Higgs decay signatures.

Contribution

It presents a novel two-loop mechanism for Dirac neutrino mass generation connected to dark matter, with symmetry protections and testable Higgs decay predictions.

Findings

Neutrino masses arise at two-loop order via dark matter sector.

Model predicts invisible Higgs decays to dark matter particles.

Enhanced sensitivity in WIMP dark matter searches below half the Higgs mass.

Abstract

We propose a "scotogenic" mechanism relating small neutrino mass and cosmological dark matter. Neutrinos are Dirac fermions with masses arising only in two--loop order through the sector responsible for dark matter. Two triality symmetries ensure both dark matter stability and strict lepton number conservation at higher orders. A global spontaneously broken U(1) symmetry leads to a physical $Diracon$ that induces invisible Higgs decays which add up to the Higgs to dark matter mode. This enhances sensitivities to spin-independent WIMP dark matter search below $m_h/2$.