Cosmology Based on f(R) Gravity Admits 1 eV Sterile Neutrinos

TL;DR

It is shown that the tension between recent neutrino oscillation experiments, favoring sterile neutrinos with masses of the order of 1 eV, and cosmological data which impose stringent constraints on neutrini masses from the free streaming suppression of density fluctuations, can be resolved in models of the present accelerated expansion of the Universe based on f(R) gravity.

Abstract

It is shown that the tension between recent neutrino oscillation experiments, favoring sterile neutrinos with masses of the order of 1 eV, and cosmological data which impose stringent constraints on neutrino masses from the free streaming suppression of density fluctuations, can be resolved in models of the present accelerated expansion of the Universe based on f(R) gravity.

Figures (2)

• Figure 1: $1\sigma$ and $2\sigma$ contours of $\sigma_8$ for the cases with three massless and one massive neutrino with the mass being $1$ eV in the ${\rm \Lambda CDM}$ model (dashed black) and $f(R)$ gravity (solid blue).
• Figure 2: CMB temperature power spectrum with WMAP7 data (upper panel) and galaxy power spectrum $b_0^2P_{\rm DM}(k)$ at $z=0.2$ with SDSS data (lower panel). The lines show the best-fitted $f(R)$ gravity (solid blue) and the best-fitted ${\rm \Lambda CDM}$ model (dashed black) in the presence of three massless and a $1$ eV massive neutrino. The difference of the best-fit $\chi^2$ between them is $\chi_{{\rm \Lambda CDM}}^2-\chi_{{\rm fRG}}^2=9.55$.