Singlet-doublet Dirac fermion dark matter from Peccei-Quinn symmetry

TL;DR

This paper proposes a multicomponent dark matter model linked to Peccei-Quinn symmetry, which allows lighter WIMP masses below 100 GeV and can be tested through neutrino telescope searches.

Contribution

It introduces a novel multicomponent dark sector model where PQ symmetry addresses the strong CP problem, generates Dirac neutrino masses, and reopens the low-mass WIMP parameter space.

Findings

Reopens the low-mass WIMP dark matter parameter space below 100 GeV.

Provides a phenomenological analysis consistent with DM direct detection, neutrino oscillations, and LFV constraints.

Suggests future tests via neutrino telescopes for DM annihilation signals.

Abstract

Weakly Interacting Massive Particles (WIMPs) and axions are arguably the most compelling dark matter (DM) candidates in the literature. Here, we consider a model where the PQ symmetry solves the strong CP problem, generates radiatively Dirac neutrino masses, and gives origin to multicomponent dark sector. Specifically, scotogenic Dirac neutrino masses arise at one-loop level. The lightest fermionic mediator acts as the second DM candidate due to a residual $Z_2$ symmetry resulting from the PQ symmetry breaking. The WIMP DM component resembles the well-known singlet-doublet fermion DM. While the lower WIMP dark mass region is usually excluded, our model reopens that portion of the parameter space (for DM masses below $\lesssim 100$ GeV). Therefore, we perform a phenomenological analysis that addresses the constraints from direct searches of DM, neutrino oscillation data, and charged lepton flavor violating (LFV) processes. The model can be tested in future facilities where DM annihilation into SM particles is searched for by neutrino telescopes.