Dark energy-dark matter interactions as a solution to the S8 tension

In this work we consider a scenario where the dark energy is a dynamical fluid whose energy density can be transferred to the dark matter via a coupling function proportional to the energy density of the dark energy. In particular, we investigate this model's ability to address the S-8 tension and find that against data from Planck, BAO and Pantheon the model (1) can significantly reduce the significance of the tension, (2) does so without exacerbating nor introducing any other tension (such as the H-0 tension) and (3) without worsening the fit to the considered data sets with respect to the Lambda CDM model. We also test the model against data from weak lensing surveys such as KiDS and DES, and find that the model's ability to address the S-8 tension further improves, without a significant impact on any other parameter nor statistical measure. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study examines a dynamic fluid model of dark energy that shows promising results in addressing the S-8 tension without significantly impacting other tensions or fit to the data sets.