A Minimal Model For Two-Component FIMP Dark Matter: A Basic Search

TL;DR

This paper introduces a minimal two-component FIMP dark matter model extending the Standard Model with three new fields, analyzing relic density and detection signals in a freeze-in scenario, highlighting self-interaction as a key probe.

Contribution

It presents a novel minimal two-component FIMP dark matter model with explicit Z2 symmetry, focusing on freeze-in production and self-interaction signatures.

Findings

Scalar component satisfies self-interaction constraints

Fermionic component does not meet self-interaction constraints

Model can be adapted to scalar or fermionic dark matter separately

Abstract

In the multi-component configurations of dark matter phenomenology, we propose a minimal two-component configuration which is an extension of the Standard Model with only three new fields; one scalar and one fermion interact with the thermal soup through Higgs portal, mediated by the other scalar in such a way that the stabilities of dark matter candidates are made simultaneously by an explicit $Z_2$ symmetry. Against the most common freeze-out framework, we look for dark matter particle signatures in the freeze-in scenario by evaluating the relic density and detection signals. A simple distinguishing feature of the model is the lack of dark matter conversion, so the dark matter components act individually and the model can be adapted entirely to both singlet scalar and singlet fermionic models, separately. We find dark matter self-interaction as the most promising approach to probe such feeble models. Although the scalar component satisfies this constraint, the fermionic one refuses it even in the resonant region.