Dark Matter Interpretation of the Neutron Decay Anomaly

Abstract

There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final state. If any of these particles are stable, they can be the dark matter. We construct representative particle physics models consistent with all experimental constraints.

5 pages, 2 figures; v2: references added, further nuclear physics experimental signatures proposed; v3: published PRL version with an extended section on $n \rightarrow χ\ e^+ e^-$ and some inline equations highlighted for visibility