Self-interacting Dark Matter and Invisibly Decaying Higgs

TL;DR

This work investigates self-interacting dark matter (SIDM) scenarios to address small-scale structure problems in CDM by proposing a scalar gauge singlet φ coupled to the Higgs via a Higgs-portal interaction. The model yields a calculable self-interaction cross section and relic density, linking halo physics to collider phenomenology through an invisible Higgs channel. It identifies a viable parameter regime (m_φ ~ MeV–GeV, λ_φ in the 1 kpc–1 Mpc range, Ω_φ ~ Ω_DM) while noting tensions with gravitational lensing bounds, and rules out a non-Newtonian force carrier as SIDM due to suppressed self-interactions. The work emphasizes collider searches for invisible Higgs decays and astrophysical tests against halo simulations as the path to validation.

Abstract

Self-interacting dark matter has been suggested in order to overcome the difficulties of the Cold Dark Matter model on galactic scales. We argue that a scalar gauge singlet coupled to the Higgs boson, which could lead to an invisibly decaying Higgs, is an interesting candidate for this self-interacting dark matter particle. We also present estimates on the abundance of these particles today as well as consequences to non-Newtonian forces.