Dark population transfer mechanism for sterile neutrino dark matter

TL;DR

This paper proposes a novel two-step mechanism for generating sterile neutrino dark matter, involving initial production of heavy sterile neutrinos and their subsequent transfer to lighter sterile neutrinos, potentially evading current detection bounds.

Contribution

The paper introduces a new cosmological production mechanism for sterile neutrino dark matter involving self-interaction-mediated transfer, distinct from existing models.

Findings

Produces relic density of sterile neutrinos consistent with dark matter

Evades current electromagnetic and structure bounds

Potentially detectable by future observations

Abstract

We present a mechanism for producing a cosmologically-significant relic density of one or more sterile neutrinos. This scheme invokes two steps: First, a population of "heavy" sterile neutrinos is created by scattering-induced decoherence of active neutrinos; Second, this population is transferred, via sterile neutrino self-interaction-mediated scatterings and decays, to one or more lighter mass ($\sim 10\,{\rm keV}$ to $\sim 1\,{\rm GeV}$) sterile neutrinos that are far more weakly (or not at all) mixed with active species and could constitute dark matter. Dark matter produced this way can evade current electromagnetic and structure-based bounds, but may nevertheless be probed by future observations.