Dark matter component decaying after recombination: constraints from diffuse gamma-ray and neutrino flux measurements

We consider scenario of the dark matter consisting of two fractions, stable part being dominant and a smaller unstable fraction, which has decayed after the recombination epoch. It has been suggested in Ref. [arxiv:1505.03644] that the above scenario may alleviate tension between high-redshift (CMB anisotropy) and low-redshift (cepheid variables and SNe Ia, cluster counts) cosmological measurements. We derive constraints on the heavy relics branching to $q\bar{q}$, $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$, ${\tau }^{+}{\tau }^{-}$, ${\nu }_e\overline{{\nu }_e}$, ${\nu }_{\mu }\overline{{\nu }_{\mu }}$, $W^{+}{W}^{-}$ and $\gamma \gamma$ in the above scenario by comparison of the secondary $\gamma$ and $\nu$ fluxes produced by the process with recent diffuse $\gamma$ and $\nu$ flux measurements.