Thermally produced scalar singlet as leptonphilic dark matter

TL;DR

This paper introduces a simple extension of the Standard Model with a scalar singlet and a leptonphilic scalar doublet, proposing the scalar singlet as a thermally produced dark matter candidate that can explain cosmic electron/positron excesses.

Contribution

It presents a novel model where a scalar singlet acts as dark matter and leverages Breit--Wigner resonance to enhance annihilation cross-sections.

Findings

Scalar singlet can account for dark matter relic abundance.

Enhanced annihilation cross-section fits cosmic electron/positron excess.

Model consistent with gamma-ray background constraints.

Abstract

This work proposes a simple extension of the Standard Model where a scalar singlet and a leptonphilic scalar doublet exist. The scalar singlet could act as thermally produced dark matter. It annihilates into leptons through $s$-channel and benefit from the Breit--Winger resonance, so current thermally averaged cross-section are greatly enhanced. The constraints from the isotropic diffuse $\gamma$-ray background and correct dark matter relic abundance are analyzed. We find that the enhanced cross-section could fit the needed cross-section to explain the cosmic electron/positron excess.