Reconciling Planck results with low redshift astronomical measurements

TL;DR

This paper proposes a model where dark matter is composed of both stable and unstable components to reconcile discrepancies between Planck CMB measurements and low-redshift astronomical observations.

Contribution

It introduces a two-fraction dark matter model that explains the tension between cosmological parameters derived from CMB and local measurements.

Findings

Unstable dark matter fraction is about 10% at recombination.

The model reduces the tension between Planck data and low-redshift measurements.

Stable dark matter remains the dominant component.

Abstract

We show that emerging tension between the direct astronomical measurements at low redshifts and cosmological parameters deduced from the Planck measurements of the CMB anisotropies can be alleviated if the dark matter consists of two fractions, stable part being dominant and a smaller unstable fraction. The latter constitutes $\sim 10$ per cent at the recombination epoch if decays by now.