Constraint on ultralight Nelson-Barr dark matter from time-dependent nuclear decay

TL;DR

This paper explores how ultralight scalar dark matter in the Nelson-Barr framework could cause observable periodic variations in nuclear decay rates, providing new constraints based on experimental data.

Contribution

It introduces a novel connection between Nelson-Barr dark matter and time-dependent nuclear decay rates, deriving bounds from experimental decay data.

Findings

Derived new exclusion bounds on Nelson-Barr dark matter parameters.

Showed that scalar DM induces periodic modulations in nuclear decay rates.

Linked decay anomalies to ultralight scalar dark matter effects.

Abstract

Many experiments have notably reported anomalies in radioactive decay rates with periodic variations and challenged the traditional belief of time-independent decays. This periodicity could potentially be explained by the presence of a periodic dark matter (DM) candidate. In this work, we investigate the impact of time-dependent nuclear decay rates on the ultralight scalar DM in Nelson-Barr solution to the strong CP problem. The light scalar DM field in this framework induces periodic modulations of both CKM matrix elements and quark mass parameters. These modulations generate corresponding periodic perturbations in the neutron-proton mass difference and nuclear binding energies. Consequently, nuclear decay rates receive oscillating residuals. By analyzing the tritium decay rate, we derive new exclusion bounds on the Nelson-Barr DM parameters.