# Comment on "Neutron lifetime and dark decay of the neutron and hydrogen''

## TL;DR

This paper critiques Berezhiani's proposed neutron decay model into mirror neutrons, showing it conflicts with experimental data unless significant symmetry breaking occurs, thus questioning its viability.

## Contribution

It provides a critical analysis of the proposed neutron mirror decay model, highlighting its experimental inconsistencies and the need for extreme symmetry breaking for viability.

## Key findings

- The model is inconsistent with existing experiments.
- Significant Z2 symmetry breaking is required for the model to work.
- The critique challenges the proposed solution to neutron lifetime discrepancies.

## Abstract

The manuscript by Berezhiani (arXiv:1812.11089) proposes a model that has the neutron decaying into a mirror neutron with a branching fraction of 1%, alleviating the tension between neutron lifetime measurements in beam vs bottle experiments. We show that the model as proposed is inconsistent with experiment. Variations of the model may work at the expense of extreme breaking of the $Z_2$ symmetry between the Standard Model and its mirror copy.