Cosmology seeking friendship with sterile neutrinos

TL;DR

This paper investigates the compatibility of sterile neutrinos with cosmological data, suggesting that one or two sterile neutrinos with sub-eV mass are consistent with current observations from multiple cosmological probes.

Contribution

It provides updated constraints on sterile neutrino properties using a combination of recent cosmological datasets, supporting their potential existence within certain parameter ranges.

Findings

Compatible with one or two sterile neutrinos in sub-eV mass range

Supports sterile neutrino existence as suggested by LSND and MiniBooNE

Constraints derived from WMAP, ACBAR, BICEP, QuAD, SDSS, and HST data

Abstract

Precision cosmology and big-bang nucleosynthesis mildly favor extra radiation in the universe beyond photons and ordinary neutrinos, lending support to the existence of low-mass sterile neutrinos. We use the WMAP 7-year data, small-scale CMB observations from ACBAR, BICEP and QuAD, the SDSS 7th data release, and measurement of the Hubble parameter from HST observations to derive credible regions for the assumed common mass scale m_s and effective number N_s of thermally excited sterile neutrino states. Our results are compatible with the existence of one or perhaps two sterile neutrinos, as suggested by LSND and MiniBooNE, if m_s is in the sub-eV range.