Light sterile neutrinos and pseudoscalar interactions in cosmology

TL;DR

This paper explores how introducing pseudoscalar interactions for sterile neutrinos can reconcile laboratory anomalies with cosmological observations, improving compatibility with CMB data and local Hubble measurements.

Contribution

It demonstrates that pseudoscalar interactions enable sterile neutrino models to align with cosmological data, resolving previous conflicts.

Findings

Pseudoscalar interactions allow sterile neutrino masses compatible with SBL anomalies.

Such interactions improve the fit between cosmological data and local Hubble measurements.

The model offers a viable solution to the tension between laboratory and cosmological neutrino data.

Abstract

The Short BaseLine (SBL) neutrino oscillations anomalies hint at the presence of a sterile neutrino with a mass of around 1 eV. However, such neutrino is highly incompatible with the cosmological data, in particular from the Cosmic Microwave Background (CMB), if no new physics is assumed. An interesting possibility for reconciling the 1 eV sterile neutrino presence in cosmology is related to the existence of a new pseudoscalar interaction. If the sterile neutrinos experience such a pseudoscalar interaction, the cosmological analyses of the full CMB data prefer a sterile neutrino mass that is fully compatible with the SBL determinations. The additional interaction allows to obtain also an improved compatibility of the cosmological predictions with the local measurements of the Hubble parameter.