Dark matter in the scale-invariant 3-3-1-1 model

TL;DR

This paper introduces a scale-invariant 3-3-1-1 model that naturally incorporates dark matter candidates and explains fermion mass hierarchies through a universal seesaw mechanism, with testable predictions for dark matter detection.

Contribution

It presents a novel scale-invariant 3-3-1-1 model with a universal seesaw mechanism and a stable fermionic dark matter candidate, linking symmetry breaking to fermion masses and dark matter phenomenology.

Findings

Dark matter candidate satisfies relic density and direct detection constraints.

Mass range for dark matter is 160 GeV to 520 GeV, depending on symmetry-breaking scale.

Model predicts signals near future experimental sensitivities.

Abstract

We propose a scale-invariant model with the 3-3-1-1 gauge symmetry that features universal seesaw for all fermion masses. The discrete remnant of the gauge group, the matter parity, stabilizes a fermionic dark matter candidate. The scalar sector contains two triplets, the minimum number to break the 3-3-1 symmetry, and two scalar singlets. With the help of additional vector-like quarks, the universal implementation of the see-saw mechanism across all fermion sectors provides a partial explanation for the observed hierarchy of masses for charged leptons, neutrinos, and quarks. We identify the lightest $ P_M $-odd fermion, $ f_\mathrm{d} $, as a viable dark matter candidate. This fermion satisfies the relic density constraint and the spin-independent constraints within the mass range $ 160 \, \textrm{GeV} \lesssim m_{f_\mathrm{d}} \lesssim 520$ GeV . This range depends on the symmetry-breaking scale $ v_\chi $ with a lower bound $ v_\chi \gtrsim 3.6$ TeV due to LEP bounds on the $ \rho_0 $ parameter. Spin-independent scattering cross-sections for $ f_\mathrm{d} $ align with experimental limits from LZ and PandaX-4T, with some regions of the parameter space nearing the sensitivity of upcoming experiments, such as XLZD and PandaX-xT, which offers promising opportunities for detection.