2008/12/12 by M. A. Acero, Mario A. Acero, Julien Lesgourgues +1 · 51 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #MiniBooNE #Neutrino #Neutrino Physics Research #Neutrino oscillation #Particle physics #Particle physics theoretical and experimental studies #Physics #Sterile neutrino #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.79.045026
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 79(4) (American Physical Society) · 18 pages, 6 figures
arxiv created 2008/12/12 · openalex publication_date 2009/02/27 · arxiv updated 2010/04/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Although the MiniBooNE experiment has severely restricted the possible existence of light sterile neutrinos, a few anomalies persist in oscillation data, and the possibility of extra light species contributing as a subdominant hot (or warm) component is still interesting. In many models, this species would be in thermal equilibrium in the early universe and share the same temperature as active neutrinos, but this is not necessarily the case. In this work, we fit up-to-date cosmological data with an extended \ensuremathΛCDM model, including light relics with a mass typically in the range 0.1--10 eV. We provide, first, some nearly model-independent constraints on their current density and velocity dispersion, and second, some constraints on their mass, assuming that they consist either in early decoupled thermal relics, or in nonresonantly produced sterile neutrinos. Our results can be used for constraining most particle-physics-motivated models with three active neutrinos and one extra light species. For instance, we find that at the 3\ensuremathσ confidence level, a sterile neutrino with mass ms=2 eV can be accommodated with the data provided that it is thermally distributed with Ts/T_\ensuremathνid\ensuremath\lesssim0.8 or nonresonantly produced with \ensuremathΔNeff\ensuremath\lesssim0.5. The bounds become dramatically tighter when the mass increases. For ms\ensuremath\lesssim0.9 eV and at the same confidence level, the data is still compatible with a standard thermalized neutrino.