Unified Scenario for Composite Right-Handed Neutrinos and Dark Matter

TL;DR

This paper proposes a unified composite dark sector model where dark matter and neutrino masses originate from dark quarks, predicting distinctive collider signals and potential gravitational wave signatures.

Contribution

It introduces a minimal effective theory linking dark sector dynamics to neutrino masses and dark matter, with a UV completion and testable collider and gravitational wave predictions.

Findings

Dark kaons as dark matter candidates.

Dark neutrons as right-handed neutrinos.

Collider signals including Higgs decays with displaced vertices.

Abstract

We entertain the possibility that neutrino masses and dark matter (DM) originate from a common composite dark sector. A minimal effective theory can be constructed based on a dark $SU(3)_D$ interaction with three flavors of massless dark quarks; electroweak symmetry breaking gives masses to the dark quarks. By assigning a $\mathbb Z_2$ charge to one flavor, a stable "dark kaon" can provide a good thermal relic DM candidate. We find that "dark neutrons" may be identified as right handed Dirac neutrinos. Some level of "neutron-anti-neutron" oscillation in the dark sector can then result in non-zero Majorana masses for light Standard Model neutrinos. A simple ultraviolet completion is presented, involving additional heavy $SU(3)_D$-charged particles with electroweak and lepton Yukawa couplings. At our benchmark point, there are "dark pions" that are much lighter than the Higgs and we expect spectacular collider signals arising from the UV framework. This includes the decay of the Higgs boson to $\tau \tau \ell \ell^{\prime}$, where $\ell$($\ell'$) can be any lepton, with displaced vertices. We discuss the observational signatures of this UV framework in dark matter searches and primordial gravitational wave experiments; the latter signature is potentially correlated with the $H \to \tau \tau \ell \ell^{\prime}$ decay.