Probing multicomponent FIMP scenarios with gamma-ray telescopes

TL;DR

This paper explores a multicomponent FIMP dark matter model where decay signals from the heavier component could be detected by gamma-ray telescopes, providing a new way to observe elusive dark matter particles.

Contribution

It introduces a novel multicomponent FIMP scenario with decay channels that produce observable gamma-ray signals, linking dark matter production to potential astrophysical detections.

Findings

Decay rates can be within detectable range for gamma-ray telescopes.

Model parameters consistent with observed dark matter abundance.

Decay channels include fermionic and scalar FIMP transitions.

Abstract

We consider a scenario where the dark sector includes two Feebly Interacting Massive Particles (FIMPs), with couplings to the Standard Model particles that allow their production in the Early Universe via thermal freeze-in. These couplings generically lead to the decay of the heavier dark matter component into the lighter, possibly leading to observable signals of the otherwise elusive FIMPs. Concretely, we argue that the loop induced decay $\psi_2\rightarrow\psi_1\gamma$ for fermionic FIMPs, or $\phi_2\rightarrow\phi_1\gamma\gamma$ for scalar FIMPs, could have detectable rates for model parameters compatible with the observed dark matter abundance.