Generalized Lomb-Scargle analysis of $\rm{^{36}Cl}$ decay rate measurements at PTB and BNL

TL;DR

This study reanalyzes $ m{^{36}Cl}$ decay data from PTB and BNL using the generalized Lomb-Scargle periodogram to verify claims of solar neutrino flux influence on decay rates, finding no significant modulation.

Contribution

It applies the generalized Lomb-Scargle method to existing decay data, providing an independent verification and more robust significance testing of potential periodic signals.

Findings

PTB data shows no significant sinusoidal modulations, consistent with prior analysis.

BNL data shows some peaks at similar frequencies to previous claims, but with lower significance.

Analysis codes and datasets are publicly available for transparency and further research.

Abstract

Recently, Pomme et al did an analysis of $\rm{^{36}Cl} $ radioactive decay data from measurements at the Physikalisch-Technische Bundesanstalt (PTB), in order to verify the claims by Sturrock and collaborators of an influence on beta-decay rates measured at Brookehaven National Lab (BNL) due to the rotation-induced modulation of the solar neutrino flux. Their analysis excluded any sinusoidal modulations in the frequency range from 0.2-20/year. We carry out an independent analysis of the same PTB and BNL data using the generalized Lomb-Scargle periodogram, to look for any statistically significant peaks in the range from 0 to 14 per year, and by evaluating the significance of every peak using multiple methods. Our results for the PTB data are in agreement with those by Pomme et al. For BNL data, we do find peaks at some of the same frequencies as Sturrock et al, but the significance is much lower. All our analysis codes and datasets have been made publicly available.