Bound-state effects for dark matter with Higgs-like mediators

TL;DR

This study investigates how scalar-mediated interactions influence dark matter relic abundance, revealing that Higgs-like mediators can significantly extend the viable mass range of dark matter particles.

Contribution

It introduces a plasma-modified Schrödinger equation approach to analyze scalar exchange effects on dark matter relic abundance in a U(1)' extended Standard Model.

Findings

Dark-Higgs exchange increases overclosure bounds.

Dark matter mass limits are extended from 5 TeV to 27 TeV.

Yukawa coupling strength significantly impacts mass bounds.

Abstract

In this paper we study the impact of a scalar exchange on the dark matter relic abundance by solving a plasma-modified Schroedinger equation. A simplified model is considered where a Majorana dark matter fermion is embedded in a U(1)$'$ extension of the Standard Model and couples with a dark Higgs via a Yukawa interaction. We find that the dark-Higgs exchange can increase the overclosure bounds significantly. For the largest (smallest) value of the Yukawa coupling examined in this work, the dark matter mass is lifted from 5 TeV (0.55 TeV) to 27 TeV (0.70 TeV).