Pseudoscalar - sterile neutrino interactions: reconciling the cosmos with neutrino oscillations

TL;DR

This paper explores a pseudoscalar-mediated interaction in sterile neutrinos, reconciling short baseline oscillation anomalies with cosmological observations, and aligning the Hubble parameter with local measurements.

Contribution

It introduces a pseudoscalar interaction model that makes sterile neutrino properties compatible with both neutrino oscillation data and cosmological constraints.

Findings

CMB data favor a sterile neutrino mass compatible with SBL anomalies

The model predicts a Hubble parameter consistent with local measurements

Reconciles sterile neutrino existence with cosmological observations

Abstract

The Short BaseLine (SBL) neutrino oscillation anomalies hint at the presence of a sterile neutrino with a mass of around 1 eV. However, such a neutrino is incompatible with cosmological data, in particular observations of the Cosmic Microwave Background (CMB) anisotropies. However, this conclusion can change by invoking new physics. One possibility is to introduce a secret interaction in the sterile neutrino sector mediated by a light pseudoscalar. In this pseudoscalar model, CMB data prefer a sterile neutrino mass that is fully compatible with the mass ranges suggested by SBL anomalies. In addition, this model predicts a value of the Hubble parameter which is completely consistent with local measurements.