Sterile Neutrino Shape-shifting Caused by Dark Matter

TL;DR

This paper proposes a cosmologically consistent model where sterile neutrino masses vary across spacetime due to coupling with ultralight scalar dark matter, reconciling terrestrial hints with astrophysical constraints.

Contribution

It introduces a novel mechanism where sterile neutrino mass is sourced by dark matter, allowing for spatial and temporal variation to satisfy multiple observational constraints.

Findings

Sterile neutrino mass varies across spacetime.

Model aligns terrestrial hints with astrophysical constraints.

Dark matter scalar can source neutrino mass dynamically.

Abstract

Light sterile neutrinos with a mass of $\sim 1$ eV continue to be interesting due to multiple hints from terrestrial experiments. This simple hypothesis suffers from strong astrophysical constraints, in particular from the early universe as well as solar neutrinos. We develop a cosmologically viable proposal consistent with the terrestrial hints, as well as solar constraints, by sourcing the sterile neutrino's mass from ordinary matter via an ultralight scalar $\phi$ which can also be the dark matter. In this scenario, the experimentally implied $\sim 1$ eV sterile neutrino mass is a local value and changes throughout spacetime.