Confronting global 21-cm signal with $\mathbb{Z}_3$ symmetric dark matter models

TL;DR

This paper explores how $ ext{Z}_3$ symmetric dark matter models, specifically semi-annihilating dark matter and Co-SIMP interactions, can impact the global 21-cm signal and remain consistent with cosmological data, offering potential explanations for observed features.

Contribution

It introduces and analyzes the effects of $ ext{Z}_3$ symmetric dark matter models on the 21-cm signal, highlighting the Co-SIMP model's natural explanation for the EDGES absorption feature.

Findings

Co-SIMP model can explain EDGES dip via intrinsic cooling.

Semi-annihilating dark matter performs better with excess radio background.

Models remain viable despite debates on EDGES and SARAS 3 data.

Abstract

While the $\mathbb{Z}_3$ symmetric dark matter models have shown tremendous prospects in addressing a number of (astro-)particle physics problems, they can leave interesting imprints on cosmological observations as well. We consider two such promising models: semi-annihilating dark matter (SADM) and Co-SIMP $2\rightarrow 3$ interaction, and investigate their effects on the global 21-cm signal. SADM alone cannot address the EDGES dip but can perform better with the aid of an excess radio background, whereas Co-SIMP can naturally explain the EDGES absorption feature by virtue of an intrinsic cooling effect without invoking any such excess radiation. Hence, the latter model turns out to be a rare model within the domain of CDM, that uses leptophilic interaction to achieve the EDGES dip. Further, keeping in mind the ongoing debate between EDGES and SARAS 3 on the global 21-cm signal, we demonstrate that our chosen models can still remain viable in this context, even if the EDGES data requires reassessment in future. We then extend our investigation to possible reflections on the Dark Ages, followed by a consistency check with the CMB and BAO observations via Planck 2018(+BAO) datasets. This work thus presents a compelling case of exploring these interesting particle physics models in the light of different cosmological observations.