Thermalisation of light sterile neutrinos in the early universe

Abstract

Recent cosmological data favour additional relativistic degrees of freedom beyond the three active neutrinos and photons, often referred to as 'dark' radiation. Light sterile neutrinos is one of the prime candidates for such additional radiation. However, constraints on sterile neutrinos based on the current cosmological data have been derived using simplified assumptions about thermalisation of the sterile neutrino at the Big Bang Nucleosynthesis (BBN) epoch. These assumptions are not necessarily justified and here we solve the full quantum kinetic equations in the (1 active + 1 sterile) scenario and derive the number of thermalised species just before BBN begins (T~1MeV) for null (L=0) and large (L=0.01) initial lepton asymmetry and for a range of possible mass-mixing parameters. We find that the full thermalisation assumption during the BBN epoch is justified for initial small lepton asymmetry only. Partial or null thermalisation occurs when the initial lepton asymmetry is large.

19 pages, several figures. Identical to published version, only minor changes to original arXiv version

References in corpus (19)

• The Reactor Antineutrino Anomaly
• Phenomenology with Massive Neutrinos
• Primordial Nucleosynthesis in the Precision Cosmology Era
• Probing cosmological parameters with the CMB: Forecasts from full Monte Carlo simulations
• Cosmology seeking friendship with sterile neutrinos
• Sterile neutrinos with eV masses in cosmology -- how disfavoured exactly?
• Robust Cosmological Bounds on Neutrinos and their Combination with Oscillation Results
• Implications of 3+1 Short-Baseline Neutrino Oscillations
• Observational bounds on the cosmic radiation density
• Using BBN in cosmological parameter extraction from CMB: a forecast for Planck
• Sterile Neutrinos in Light of Recent Cosmological and Oscillation Data: a Multi-Flavor Scheme Approach
• Sterile neutrinos, lepton asymmetries, primordial elements: how much of each?
• Relic density of neutrinos with primordial asymmetries
• Constraining The Universal Lepton Asymmetry
• Searching for sterile neutrinos in ice
• Neutrino masses and cosmic radiation density: Combined analysis
• MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations
• Evidence for extra radiation? Profile likelihood versus Bayesian posterior
• Constraints on massive sterile plus active neutrino species in non minimal cosmologies

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