Mirror matter can alleviate the cosmological lithium problem

TL;DR

This paper explores how the existence of a mirror world with neutron oscillations could provide a late-time neutron injection, reducing lithium-7 abundance and addressing the cosmological lithium problem.

Contribution

It introduces a model involving neutron oscillations into mirror neutrons that can potentially resolve the lithium-7 discrepancy in big bang nucleosynthesis.

Findings

Mirror neutron oscillations can increase neutron capture on beryllium-7.

The model constrains neutron oscillation times compatible with BBN.

Potential to significantly reduce lithium-7 abundance in cosmology.

Abstract

The abundance of lithium-7 confronts cosmology with a long lasting problem between the predictions of standard big bang nucleosynthesis and the baryonic density determined from the cosmic microwave background observations. This article investigates the influence of the existence of a mirror world, focusing on models in which neutrons can oscillate into mirror neutrons. Such a mechanism allows for an effective late time neutron injection, which induces an increase of the destruction of beryllium-7, due to an increase of the neutron capture, and then a decrease of the final lithium-7 abundance. Big bang nucleosynthesis sets constraints on the oscillation time between the two types of neutron and the possibility for such a mechanism to solve, or alleviate, the lithium problem is emphasized.