Search for Periodic Modulations of the Rate of Double-Beta Decay of $^{100}$Mo in the NEMO-3 Detector

TL;DR

This study used the NEMO-3 detector to search for periodic variations in the double-beta decay rate of $^{100}$Mo, finding no significant modulations within the tested frequency range and amplitude.

Contribution

First search for periodic modulations in the double-beta decay rate of $^{100}$Mo using advanced statistical techniques and Monte Carlo modeling.

Findings

No evidence of decay rate modulations above 2.5% amplitude.

Sensitivity analysis across a broad frequency range.

Established upper limits on possible periodic variations.

Abstract

Double-beta decays of $^{100}$Mo from the 6.0195-year exposure of a 6.914 kg high-purity sample were recorded by the NEMO-3 experiment that searched for neutrinoless double-beta decays. These ultra-rare transitions to $^{100}$Ru have a half-life of approximately $7\times10^{18}$ years, and have been used to conduct the first ever search for periodic variations of this decay mode. The Lomb-Scargle periodogram technique, and its error-weighted extension, were employed to look for periodic modulations of the half-life. Monte Carlo modeling was used to study the modulation sensitivity of the data over a broad range of amplitudes and frequencies. Data show no evidence of modulations with amplitude greater than 2.5% in the frequency range of $0.33225\,{\rm y^{-1}}$ to $365.25\,{\rm y^{-1}}$.