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

Roderic Mòbil

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

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dc.contributor.author Gariazzo, Stefano
dc.contributor.author Fernández de Salas, Pablo
dc.contributor.author Pastor Carpi, Sergio
dc.date.accessioned 2020-06-29T10:05:32Z
dc.date.available 2020-06-29T10:05:32Z
dc.date.issued 2019
dc.identifier.uri https://hdl.handle.net/10550/75206
dc.description.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 4×4 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, Neff, and its dependence on the three additional mixing angles (θ_14, θ_24, θ_34) and on the squared mass difference Δm^2_41 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 (Neff≃4).
dc.language.iso eng
dc.relation.ispartof Journal Of Cosmology And Astroparticle Physics, 2019, vol. 07, p. 014-1-014-29
dc.rights.uri info:eu-repo/semantics/openAccess
dc.source Gariazzo, Stefano Fernández de Salas, Pablo Pastor Carpi, Sergio 2019 Thermalisation of sterile neutrinos in the early universe in the 3+1 scheme with full mixing matrix Journal Of Cosmology And Astroparticle Physics 07 014-1 014-29
dc.subject Cosmologia
dc.subject Astrofísica
dc.title Thermalisation of sterile neutrinos in the early universe in the 3+1 scheme with full mixing matrix
dc.type info:eu-repo/semantics/article
dc.date.updated 2020-06-29T10:05:33Z
dc.identifier.doi https://doi.org/10.1088/1475-7516/2019/07/014
dc.identifier.idgrec 139261


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Roderic Mòbil