Novel neutron decay mode inside neutron stars

TL;DR

This paper investigates a novel neutron decay mode into dark matter within neutron stars, analyzing its implications for star properties, dark matter characteristics, and potential observational signals, without requiring repulsive dark matter forces.

Contribution

It introduces a new decay channel n→χχχ that aligns with neutron star constraints and explores its effects on dark matter properties and neutron star signals.

Findings

Neutron decay into three dark matter particles is compatible with neutron star observations.

Dark matter can be hot and present in the neutron star core without strong repulsive interactions.

Potential signals of neutron decay inside neutron stars after birth are discussed.

Abstract

We explore the suggestion that the neutron lifetime puzzle might be resolved by neutrons decaying into dark matter through the process, n \rightarrow \chi\chi\chi, with \chi having a mass one third of that of the neutron. In particular, we examine the consequences of such a decay mode for the properties of neutron stars. Unlike an earlier suggested decay mode, in order to satisfy the constraints on neutron star mass and tidal deformability, there is no need for a strong repulsive force between the dark matter particles. This study suggests the possibility of having hot dark matter at the core of the neutron star and presents a possible mechanism of dark matter cooling, and examines the possible signal of neutrons decaying in this way inside the neutron star right after its birth.