Resonant production of the sterile neutrino dark matter and fine-tunings in the [nu]MSM

TL;DR

This paper investigates how lepton asymmetry generated by heavier sterile neutrinos influences dark matter production in the nuMSM, emphasizing the fine-tuning required for mass degeneracy and proposing a natural model realization.

Contribution

It analyzes the renormalization group evolution of sterile neutrino masses and presents a model that naturally achieves the necessary degeneracy for dark matter production.

Findings

Degeneracy of sterile neutrino masses is crucial for dark matter production.

Renormalization group effects impact the fine-tuning of neutrino mass differences.

A natural model example demonstrates feasible low-energy degeneracy.

Abstract

The generation of lepton asymmetry below the electroweak scale has a considerable impact on production of dark matter sterile neutrinos. Oscillations or decays of the heavier sterile neutrinos in the neutrino minimal standard model can give rise to the requisite lepton asymmetry, provided the masses of the heavier neutrinos are sufficiently degenerate. We study the renormalization group evolution of the mass difference of these singlet fermions to understand the degree of necessary fine-tuning. We construct an example of the model that can lead to a technically natural realization of this low-energy degeneracy.