Thermalisation of sterile neutrinos in the early Universe in the 3+1 scheme with full mixing matrix

Abstract

In the framework of a 3+1 scheme with an additional inert state, we consider the thermalisation of sterile neutrinos in the early Universe taking into account the full $4\times 4$ mixing matrix. The evolution of the neutrino energy distributions is found solving the momentum-dependent kinetic equations with full diagonal collision terms, as in previous analyses of flavour neutrino decoupling in the standard case. The degree of thermalisation of the sterile state is shown in terms of the effective number of neutrinos, $N_{\mathrm{eff}}$, and its dependence on the three additional mixing angles (${\theta }_{14}$, ${\theta }_{24}$, ${\theta }_{34}$) and on the squared mass difference $\Delta m_{41}^2$ is discussed. Our results are relevant for fixing the contribution of a fourth light neutrino species to the cosmological energy density, whose value is very well constrained by the final Planck analysis. For the preferred region of active-sterile mixing parameters from short-baseline neutrino experiments, we find that the fourth state is fully thermalised ($N_{\mathrm{eff}}\simeq 4$).

30 pages, 10 figures. Matches published version

References in corpus (7)

• Relic neutrino decoupling with flavour oscillations revisited
• Sterile neutrino search at NEOS Experiment
• Sterile neutrino oscillations after first MiniBooNE results
• Sterile Neutrinos in Light of Recent Cosmological and Oscillation Data: a Multi-Flavor Scheme Approach
• Sterile Neutrinos or Flux Uncertainties? - Status of the Reactor Anti-Neutrino Anomaly
• Multi-momentum and multi-flavour active-sterile neutrino oscillations in the early universe: role of neutrino asymmetries and effects on nucleosynthesis
• A Combined View of Sterile-Neutrino Constraints from CMB and Neutrino Oscillation Measurements

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