2,364 research outputs found
How secret interactions can reconcile sterile neutrinos with cosmology
Short baseline neutrino oscillation experiments have shown hints of the
existence of additional sterile neutrinos in the eV mass range. However, such
neutrinos seem incompatible with cosmology because they have too large an
impact on cosmic structure formation. Here we show that new interactions in the
sterile neutrino sector can prevent their production in the early Universe and
reconcile short baseline oscillation experiments with cosmology.Comment: 4 pages, 5 figures, prepared for submission to PR
Sterile neutrinos with pseudoscalar self-interactions and cosmology
Sterile neutrinos in the electronvolt mass range are hinted at by a number of
terrestrial neutrino experiments. However, such neutrinos are highly
incompatible with data from the Cosmic Microwave Background and large scale
structure. This paper discusses how charging sterile neutrinos under a new
pseudoscalar interaction can reconcile eV sterile neutrinos with terrestrial
neutrino data. We show that this model can reconcile eV sterile neutrinos in
cosmology, providing a fit to all available data which is way better than the
standard CDM model with one additional fully thermalized sterile
neutrino. In particular it also prefers a value of the Hubble parameter much
closer to the locally measured value.Comment: 7 pages, 5 figures, uses REVTe
Cosmology with self-interacting sterile neutrinos and dark matter - A pseudoscalar model
Short baseline neutrino oscillation experiments have shown hints of the
existence of additional sterile neutrinos in the eV mass range. Such sterile
neutrinos are incompatible with cosmology because they suppress structure
formation unless they can be prevented from thermalising in the early Universe
or removed by subsequent decay or annihilation. Here we present a novel
scenario in which both sterile neutrinos and dark matter are coupled to a new,
light pseudoscalar. This can prevent thermalisation of sterile neutrinos and
make dark matter sufficiently self-interacting to have an impact on galactic
dynamics and possibly resolve some of the known problems with the standard cold
dark matter scenario. Even more importantly it leads to a strongly
self-interacting plasma of sterile neutrinos and pseudoscalars at late times
and provides an excellent fit to CMB data. The usual cosmological neutrino mass
problem is avoided by sterile neutrino annihilation to pseudoscalars. The
preferred value of is substantially higher than in standard CDM
and in much better agreement with local measurements.Comment: 8 pages, 4 figures, matches published versio
Pseudoscalar - sterile neutrino interactions: reconciling the cosmos with neutrino oscillations
The Short BaseLine (SBL) neutrino oscillation anomalies hint at the presenceof a sterile neutrino with a mass of around 1 eV. However, such a neutrino isincompatible with cosmological data, in particular observations of the CosmicMicrowave Background (CMB) anisotropies. However, this conclusion can change byinvoking new physics. One possibility is to introduce a secret interaction inthe sterile neutrino sector mediated by a light pseudoscalar. In thispseudoscalar model, CMB data prefer a sterile neutrino mass that is fullycompatible with the mass ranges suggested by SBL anomalies. In addition, thismodel predicts a value of the Hubble parameter which is completely consistentwith local measurements
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