A Global Analysis of Resonance-enhanced Light Scalar Dark Matter

TL;DR

This paper investigates a minimal light scalar dark matter model with a mediator, analyzing resonance effects, relic abundance, and detection constraints, highlighting the potential for future gamma-ray observations to explore uncharted parameter space.

Contribution

It provides a comprehensive analysis of resonance-enhanced light scalar dark matter, including relic abundance and detection constraints, focusing on the unexplored 0.3-2 GeV mass range.

Findings

Scalar dark matter of 0.3-2 GeV remains untested.

Resonance effects significantly influence relic abundance.

Future MeV gamma-ray observations can probe this parameter space.

Abstract

We study a minimal model for a light scalar dark matter, requiring a light scalar mediator to address the core-cusp problem and interact with the standard model particles. We analyze the model comprehensively by focusing on the Breit-Wigner resonance for dark matter annihilation and self-scattering channels, considering the thermal relic abundance condition that includes the early kinetic decoupling effect, as well as the present and future constraints from collider, direct, and indirect dark matter detections. We found that the scalar dark matter with the mass of 0.3-2 GeV remains uncharted, which will be efficiently tested by the near future MeV gamma-ray observations.