Cosmology seeking friendship with sterile neutrinos
Hamann, Jan and Hannestad, Steen and Raffelt, Georg G. and Tamborra, Irene and Wong, Yvonne Y. Y.
Keywords
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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 release, small-scale CMB observations from ACBAR, BICEP and QuAD, the 7th data release of the Sloan Digital Sky Survey, and measurement of the Hubble parameter from Hubble Space Telescope 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 interpretation of the LSND and MiniBooNE anomalies in terms of 3 active _s16 2 sterile neutrinos if m_s is in the sub-eV range.
