Can decaying dark matter scenarios alleviate both H0 and σ8 tensions?

Current tensions in cosmological parameters, including H-0 and sigma(8), provide a strong reason to suspect the existence of physics beyond the standard model of cosmology (?CDM). In this work, we investigate whether there is a relation between these tensions and beyond cold dark matter (CDM) scenarios. To model non-cold dark matter, we assume decaying dark matter (DDM) that is unstable and may decay into two daughter particles, a combination of cold dark matter, warm dark matter (WDM), and dark radiation, to explore a vast era of possibilities. We check our model against CMB data and show that decaying dark matter does not seem a promising candidate to address cosmological tensions. As an exception to this, when DDM decays to CDM + WDM there are hints that H-0 tension may be addressed.

Automated summary

The current tensions in cosmological parameters raise doubts about the standard model of cosmology. This research investigates the relation between these tensions and scenarios beyond cold dark matter, specifically focusing on decaying dark matter. The findings suggest that decaying dark matter is not a promising candidate for addressing the cosmological tensions, except when it decays into cold dark matter and warm dark matter.