Self-interacting Dark Matter with Scalar Dilepton Mediator

TL;DR

This paper proposes a scalar dilepton mediator model for self-interacting dark matter that addresses small-scale structure issues, aligns with observational constraints, and offers a viable relic density consistent with cosmological data.

Contribution

It introduces a leptonic scalar dark matter model with a light mediator, demonstrating its ability to resolve small-scale structure problems and satisfy experimental constraints.

Findings

Identifies parameter regions with correct relic density.

Satisfies constraints from direct and indirect detection.

Resolves discrepancies between observations and simulations.

Abstract

The cold dark matter (CDM) candidate with weakly interacting massive particles can successfully explain the observed dark matter relic density in cosmic scale and the large-scale structure of the Universe. However, a number of observations at the satellite galaxy scale seem to be inconsistent with CDM simulation. This is known as the small-scale problem of CDM. In recent years, it has been demonstrated that self-interacting dark matter (SIDM) with a light mediator offers a reasonable explanation for the small-scale problem. We adopt a simple model with SIDM and focus on the effects of Sommerfeld enhancement. In this model, the dark matter candidate is a leptonic scalar particle with a light mediator. We have found several regions of the parameter space with proper masses and coupling strength generating a relic density that is consistent with the observed CDM relic density. Furthermore, this model satisfies the constraints of recent direct searches and indirect detection for dark matter as well as the effective number of neutrinos and the observed small-scale structure of the Universe. In addition, this model with the favored parameters can resolve the discrepancies between astrophysical observations and $N$-body simulations.