Cosmology based on \(f(R)\) gravity with \({\cal O}(1)\) eV sterile neutrino

• Published in: arXiv.org 2015-05
• Main Authors: Chudaykin, A S, Gorbunov, D S, Starobinsky, A A, Burenin, R A
• Format: Article
• Language: English
• Subjects: Anisotropy; Anomalies; Astronomical models; Big Bang theory; Clusters; Cosmic microwave background; Cosmological constant; Cosmology; Damping; Dark energy; Gravitation; Hubble constant; Neutrinos; Relativity; Universe
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1412.5239

We address the cosmological role of an additional \({\cal O}(1)\) eV sterile neutrino in modified gravity models. We confront the present cosmological data with predictions of the FLRW cosmological model based on a variant of \(f(R)\) modified gravity proposed by one of the authors previously. This viable cosmological model which deviation from general relativity with a cosmological constant \(\Lambda\) decreases as \(R^{-2n}\) for large, but not too large values of the Ricci scalar \(R\) provides an alternative explanation of present dark energy and the accelerated expansion of the Universe. Various up-to-date cosmological data sets exploited include Planck CMB anisotropy, CMB lensing potential, BAO, cluster mass function and Hubble constant measurements. We find that the CMB+BAO constraints strongly the sum of neutrino masses from above. This excludes values \(\lambda\sim 1\) for which distinctive cosmological features of the model are mostly pronounced as compared to the \(\Lambda\)CDM model, since then free streaming damping of perturbations due to neutrino rest masses is not sufficient to compensate their extra growth occurring in \(f(R)\) gravity. Thus, we obtain \(\lambda>8.2\) (\(2\sigma\)) with cluster systematics and \(\lambda>9.4\) (\(2\sigma\)) without that. In the latter case we find for the sterile neutrino mass $0.47\,\,\rm{eV}$$\,