Theoretical bounds on dark Higgs mass in a self-interacting dark matter model with $U(1)'$

TL;DR

This paper derives theoretical bounds on the dark Higgs mass in a self-interacting dark matter model with a broken $U(1)'$ gauge symmetry, integrating these bounds with observational data to constrain the model's parameter space.

Contribution

It provides gauge and scale independent theoretical bounds on the dark Higgs mass and explores their implications for dark matter phenomenology.

Findings

Dark matter mass range: 10-500 GeV

Mediator (dark photon) mass: 0.5-5 MeV

Dark Higgs mass: 0.05-50 MeV

Abstract

Motivated by the null results of current dark matter searches and the small-scale problems, we study a dark sector charged by a spontaneous broken gauge $U(1)'$. To explore the parameter space of this model, in addition to the consideration of the small-scale data, we also consider the theoretical bounds on the dark Higgs mass, with the upper bound coming from the tree-level perturbative unitarity and the lower bound from the one-loop Linde-Weinberg bound. We deeply examine the dependence of the Linde-Weinberg bound on gauge choice and energy scale, and present a Linde-Weinberg bound that is gauge and scale independent. Combining the theoretical and observational constraints, we obtain the following ranges for the parameter space: the dark matter mass is 10-500 GeV, the mediator (dark photon) mass is 0.5-5 MeV, the dark Higgs mass is 0.05-50 MeV, and the dark fine-structure constant is 0.001-0.4. We conclude that the dark Higgs in this model cannot be ignored in the phenomenological study of the dark sector.