Neutron Dark Decay

TL;DR

This paper reviews the hypothesis that neutron dark decay could explain the experimental discrepancy in neutron lifetime measurements, discussing theoretical models and future experimental tests for this beyond-Standard-Model decay channel involving dark matter candidates.

Contribution

It provides a comprehensive review of the theoretical models and experimental efforts related to neutron dark decay as a solution to the lifetime discrepancy.

Findings

Current models accommodate neutron dark decay involving dark matter particles.

Experimental efforts are ongoing to detect or constrain neutron dark decay channels.

The neutron lifetime discrepancy might be explained by a new decay mode involving dark particles.

Abstract

There exists a puzzling disagreement between the results for the neutron lifetime obtained in experiments using the beam technique versus those relying on the bottle method. A possible explanation of this discrepancy postulates the existence of a beyond-Standard-Model decay channel of the neutron involving new particles in the final state, some of which can be dark matter candidates. We review the current theoretical status of this proposal and discuss the particle physics models accommodating such a dark decay. We then elaborate on the efforts undertaken to test this hypothesis, summarizing the prospects for probing neutron dark decay channels in future experiments.