Neutrino mass and secluded dark matter puzzles solved together
Year: 2026
Type: article
Abstract: We present a secluded dark-matter (DM) framework based on an extra U ( 1 ) X gauge symmetry. The model contains a Dirac DM particle χ , three heavy neutrinos N I with masses M N , I , and a singlet scalar R that mixes with the Standard Model Higgs doublet Φ by an angle α . A symmetry forbids the Φ − R portal at tree level; the leading portal then arises at one loop from the same Yukawa structures that generate active neutrino masses m ν , I , implying tan ( 2 α ) ∝ ∑ I m ν , I M N , I 2 / ( v h m H 2 ) , where v h and m H are the Standard Model Higgs vacuum-expectation-value and mass. For heavy-neutrino masses in the multi-TeV range, this yields a naturally tiny mixing, tan ( 2 α ) ∼ 5 × 10 − 11 ( M N / 10 TeV ) 2 , which strongly suppresses DM signals in direct, indirect, and collider searches. For PeV-scale heavy neutrinos the loop-induced portal is enhanced and the DM-nucleon cross section can instead enter the reach of direct-detection experiments. The visible and dark sectors thermalize at temperatures of order a few times the mass of the lightest heavy neutrino, then subsequently decouple, and typically evolve with a slightly hotter dark bath. In the secluded regime, with tan ( 2 α ) ≪ 1 and m χ > m H p , the relic density is set by p -wave annihilation χ χ ¯ → H p H p (with H p the Higgs-like particle of the dark sector), and the dark-sector Yukawa couplings required to reproduce the observed abundance are O ( 0.1
DOI: 10.1103/np7k-2fck
Author: Mattia Di Mauro
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7106852882