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

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 $160\text{GeV}\lesssim m_{f_{\mathrm{d}}}\lesssim 520$ 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.

Comments: 34 pages, 5 figures