Physical origin of "chaoticity" of neutrino asymmetry

TL;DR

This paper investigates the physical reasons behind the unpredictable sign of neutrino asymmetry generated in the early universe due to active-sterile neutrino oscillations, clarifying conflicting previous results.

Contribution

It provides a detailed analysis of the asymmetry growth dynamics and resolves discrepancies in earlier studies regarding the sign indeterminacy.

Findings

The sign of neutrino asymmetry is physically indeterminate.

The dynamics of asymmetry growth are clarified.

Contradicting previous results are reconciled.

Abstract

We consider the indeterminacy in the sign of the neutrino asymmetry generated by active-sterile neutrino oscillations in the early universe. The dynamics of asymmetry growth is discussed in detail and the indeterminacy in the final sign of the asymmetry is shown to be a real physical phenomenon. Recently published contradicting results are carefully considered and the underlying assumptions leading to the disagreement are resolved.