Exploring massive neutrinos in dark cosmologies with EFTCAMB/EFTCosmoMC

We revisit the degeneracy between massive neutrinos and generalized theories of gravity in the framework of the effective field theory of cosmic acceleration. In particular, we consider f(R) theories and a class of nonminimally coupled models parametrized via a coupling to gravity which is linear in the scale factor. In the former case, we find a slightly lower degeneracy with that found in the literature, due to the fact that we implement exact designer f(R) models and evolve the full linear dynamics of perturbations. As a consequence, our bounds are slightly tighter on the f(R) parameter but looser on the summed neutrino mass. We also set a new upper bound on the Compton wavelength parameter Log(10)B(0) < -4.1 at 95% C.L. with a fixed summed neutrino mass (Sigma m(nu) = 0.06 eV) in f(R) gravity with the combined data sets from cosmic microwave background temperature and lensing power spectra of the Planck Collaboration, as well as galaxy power spectrum from the WiggleZ dark energy survey. We do not observe a sizable degeneracy between massive neutrinos and modified gravity in the nonminimally coupled model considered, which corresponds to a peculiar case of coupling that depends linearly on the scale factor. The analysis is performed with an updated version of the EFTCAMB/EFTCosmoMC package, which is now publicly available and extends the first version of the code with the consistent inclusion of massive neutrinos, tensor modes, several alternative background histories, and designer quintessence models.