Dark sector interaction: a remedy of the tensions between CMB and LSS data

Abstract

Abstract The well-known tensions on the cosmological parameters $$H_0$$ H0 and $$\sigma _8$$ σ8 within the $$\Lambda $$ Λ CDM cosmology shown by the Planck-CMB and LSS data are possibly due to the systematics in the data or our ignorance of some new physics beyond the $$\Lambda $$ Λ CDM model. In this letter, we focus on the second possibility, and investigate a minimal extension of the $$\Lambda $$ Λ CDM model by allowing a coupling between its dark sector components (dark energy and dark matter). We analyze this scenario with Planck-CMB, KiDS and HST data, and find that the $$H_0$$ H0 and $$\sigma _8$$ σ8 tensions disappear. In the joint analyses with Planck, HST and KiDS data, we find non-zero coupling in the dark sector up to 99% CL. Thus, we find a strong statistical support from the observational data for an interaction in the dark sector of the Universe while solving the $$H_0$$ H0 and $$\sigma _8$$ σ8 tensions simultaneously.