Implications of mirror neutrinos for early universe cosmology

TL;DR

This paper explores how mirror neutrinos in the Exact Parity Model influence early universe conditions, particularly neutrino asymmetries and their effects on Big Bang Nucleosynthesis, providing detailed calculations of these phenomena.

Contribution

It offers a detailed calculation of neutrino asymmetry evolution in the six-flavour EPM, highlighting implications for early universe cosmology and element synthesis.

Findings

Mirror neutrino oscillations generate large neutrino asymmetries.

Large $ u_e$ asymmetries suppress mirror neutrino production.

Neutrino asymmetries affect light element synthesis during BBN.

Abstract

The Exact Parity Model (EPM) is, in part, a theory of neutrino mass and mixing that can solve the atmospheric, solar and LSND anomalies. The central feature of the neutrino sector is three pairs of maximally mixed ordinary and mirror neutrinos. It has been shown that ordinary-mirror neutrino oscillations can generate large neutrino asymmetries in the epoch of the early universe immediately prior to Big Bang Nucleosynthesis (BBN). The large neutrino asymmetries generically suppress the production of mirror neutrinos, and a sufficiently large $\nu_e$ asymmetry can directly affect light element synthesis through nuclear reaction rates. In this paper we present a detailed calculation of neutrino asymmetry evolution driven by the six-flavour EPM neutrino sector, focusing on implications for BBN.