Reducing the H-0 and sigma(8) tensions with dark matter-neutrino interactions

The introduction of dark matter-neutrino interactions modifies the cosmic microwave background (CMB) angular power spectrum at all scales, thus affecting the reconstruction of the cosmological parameters. Such interactions can lead to a slight increase of the value of H-0 and a slight decrease of S-8 = sigma(8) root Omega(m)/0.3, which can help reduce somewhat the tension between the CMB and weak lensing or Cepheids data sets. Here we show that it is impossible to solve both tensions simultaneously. While the 2015 Planck temperature and low multipole polarization data combined with the Cepheids data sets prefer large values of the Hubble rate (up to H-0 = 72.1(-1.7)(+1.5) km/s/Mpc, when N-eff is free to vary), the sigma(8) parameter remains too large to reduce the sigma(8) tension. Adding high multipole Planck polarization data does not help since this data shows a strong preference for low values of H-0, thus worsening current tensions, even though they also prefer smaller value of sigma(8).