Constraints on massive sterile plus active neutrino species in non minimal cosmologies

TL;DR

This paper explores how different non minimal cosmological models impact constraints on active and sterile neutrino species, finding that certain models still allow for sterile neutrinos around 0.5 eV, consistent with some experimental signals.

Contribution

It extends previous analyses to non minimal cosmologies, examining various scenarios and their effects on neutrino mass constraints and compatibility with experimental data.

Findings

(3+2) neutrino models with ~0.5 eV sterile species are allowed at 95% CL

Non minimal cosmologies can accommodate sterile neutrinos consistent with some experimental signals

Big Bang Nucleosynthesis bounds may challenge the viability of fully thermalized sterile neutrinos

Abstract

Cosmological measurements are affected by the energy density of both active and sterile massive neutrinos. We extend here a recent analysis of current cosmological data to non minimal cosmologies. Several possible scenarios are examined: a constant w \neq -1 dark energy equation of state, a non flat universe, a time varying dark energy component and coupled dark matter dark energy universes or modified gravity scenarios. When considering cosmological data only, (3+2) massive neutrino models with ~0.5 eV sterile species are allowed at 95% CL. This scenario has been shown to reconcile reactor, LSND and MiniBooNE positive signals with null results from other searches. Big Bang Nucleosynthesis bounds could compromise the viability of (3+2) models if the two sterile species are fully thermalized states at decoupling.