Neutron lifetime puzzle and neutron -- mirror neutron oscillation

TL;DR

This paper proposes that neutron to mirror neutron oscillations, enhanced by magnetic fields, explain the neutron lifetime discrepancy observed in experiments, with implications for dark matter and astrophysics.

Contribution

It introduces a novel explanation for the neutron lifetime puzzle involving neutron-mirror neutron oscillations with tiny mass splitting.

Findings

Neutron to mirror neutron oscillation can account for the lifetime discrepancy.

Resonant enhancement occurs in large magnetic fields used in beam experiments.

Phenomenological and astrophysical implications are briefly discussed.

Abstract

The discrepancy between the neutron lifetimes measured in the beam and trap experiments can be explained via the neutron $n$ conversion into mirror neutron $n'$, its dark partner from parallel mirror sector, provided that $n$ and $n'$ have a tiny mass splitting order $10^{-7}$ eV. In large magnetic fields used in beam experiments $n-n'$ transition is resonantly enhanced and can transform of about a per cent fraction of neutrons into mirror neutrons which decay in invisible mode. Thus less protons will be produced and the measured value $\tau_{\rm beam}$ appears larger than $\beta$-decay time $\tau_{\beta} = \tau_{\rm trap}$. Some phenomenological and astrophysical consequences of this scenario are also briefly discussed.