Dark matter component decaying after recombination: Lensing constraints with Planck data

Abstract

It has been recently suggested [Z. Berezhiani, A. D. Dolgov, and I. I. Tkachev, Phys. Rev. D 92, 061303 (2015)] that emerging tension between cosmological parameter values derived in high-redshift (CMB anisotropy) and low-redshift (cluster counts, Hubble constant) measurements can be reconciled in a model which contains a subdominant fraction of dark matter decaying after recombination. We check the model against the CMB Planck data. We find that lensing of the CMB anisotropies by the large-scale structure gives strong extra constraints on this model, limiting the fraction as F <8 % at 2 σ confidence level. However, investigating the combined data set of the CMB and conflicting low-z measurements, we obtain that the model with F ≈2 %- 5 % exhibits better fit (by 1.5 - 3 σ depending on the lensing priors) compared to that of the concordance Λ CDM cosmological model.