Comparative Analyses of Brookhaven National Laboratory Nuclear Decay Measurements and Super-Kamiokande Solar Neutrino Measurements: Neutrinos and Neutrino-Induced Beta-Decays as Probes of the Deep Solar Interior

Abstract

An experiment carried out at the Brookhaven National Laboratory over a period of almost 8 years acquired 364 measurements of the beta-decay rates of a sample of ${}^{32}\mbox{Si}$ and, for comparison, of a sample of ${}^{36}\mbox{Cl}$. The experimenters reported finding “small periodic annual deviations of the data points from an exponential decay … of uncertain origin”. We find that power-spectrum and spectrogram analyses of these datasets show evidence not only of the annual oscillations, but also of transient oscillations with frequencies near 11 year⁻¹ and 12.5 year⁻¹. Similar analyses of 358 measurements of the solar neutrino flux acquired by the Super-Kamiokande neutrino observatory over a period of about 5 years yield evidence of an oscillation near 12.5 year⁻¹ and another near 9.5 year⁻¹. An oscillation near 12.5 year⁻¹ is compatible with the influence of rotation of the radiative zone. We suggest that an oscillation near 9.5 year⁻¹ may be indicative of rotation of the solar core, and that an oscillation near 11 year⁻¹ may have its origin in a tachocline between the core and the radiative zone. Modulation of the solar neutrino flux may be attributed to an influence of the Sun’s internal magnetic field by the Resonant Spin Flavor Precession (RSFP) mechanism, suggesting that neutrinos and neutrino-induced beta decays can provide information about the deep solar interior.