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

Abstract

ABSTRACT Current tensions in cosmological parameters, including H0 and σ8, provide a strong reason to suspect the existence of physics beyond the standard model of cosmology (ΛCDM). 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 H0 tension may be addressed.