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Recent reports of periodic fluctuations in nuclear decay data of certain isotopes have led to the suggestion that nuclear decay rates are being influenced by the Sun, perhaps via neutrinos. Here we present evidence for the existence of an additional periodicity that appears to be related to the Rieger periodicity well known in solar physics., Performed in collaboration with Purdue University, West Lafayette, IN; and Stanford University, Stanford, CA. Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, 28 June-2 July 2010.

Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. As a test of this hypothesis, we here search for evidence in decay data that might be indicative of a process involving solar rotation, focusing on data for 32Si and 36Cl decay rates acquired at the Brookhaven National Laboratory. Examination of the power spectrum over a range of frequencies appropriate for solar synodic rotation rates reveals several periodicities, the most prominent being one at 11.18 year-1 with power 20.76. We evaluate the significance of this peak in terms of the false-alarm probability, by means of the shuffle test, and also by means of a new test that involves small random time displacements. The last two tests are the more robust, and indicate that the peak at 11.18 year-1 would arise by chance only once out of about 107 trials. However, the fact that there are several peaks in the rotational search band suggests that modulation of the count rate involves several low-Q oscillations rather than a single high-Q oscillation, possibly indicative of a partly stochastic process. To pursue this possibility, we investigate the running mean of the power spectrum, and identify a major peak at 11.93 year-1 with peak running-mean power 4.08. Application of the shuffle test indicates that there is less than one chance in 1011 of finding by chance a value as large as 4.08. Application of the shake test leads to a more restrictive result that there is less than one chance in 1015 of finding by chance a value as large as 4.08. We find that there is notable agreement in the running-mean power spectra in the rotational search band formed from BNL data and from ACRIM total solar irradiance data. Since rotation rate estimates derived from irradiance data have been found to be closely related to rotation rate estimates derived from low-energy solar-neutrino data, this result supports the recent conjecture t, Prepared in cooperation with Purdue University, IN; Edwards AFB, CA; and US Air Force Academy, CO.

We provide the results from a spectral analysis of nuclear decay data displaying annually varying periodic fluctuations. The analyzed data were obtained from three distinct data sets: Si-32 and (CI)-C-36 decays reported by an experiment performed at the Brookhaven National Laboratory (BNL), Mn-56 decay reported by the Children's Nutrition Research Center (CNRC), but also performed at BNL, and Ra-226 decay reported by an experiment performed at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. All three data sets exhibit the same primary frequency mode consisting of an annual period. Additional spectral comparisons of the data to local ambient temperature, atmospheric pressure, relative humidity, Earth-Sun distance, and their reciprocals were performed. No common phases were found between the factors investigated and those exhibited by the nuclear decay data. This suggests that either a combination of factors was responsible, or that, if it was a single factor, its effects on the decay rate experiments are not a direct synchronous modulation. We conclude that the annual periodicity in these data sets is a real effect, but that further study involving additional carefully controlled experiments will be needed to establish its origin. Published by Elsevier B.V.

Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. As a test of this hypothesis, we here search for evidence in decay data that might be indicative of a process involving solar rotation, focusing on data for Si-32 and Cl-36 decay rates acquired at the Brookhaven National Laboratory. Examination of the power spectrum over a range of frequencies (10-15 year(-1)) appropriate for solar synodic rotation rates reveals several periodicities, the most prominent being one at 11.18 year(-1) with power 20.76. We evaluate the significance of this peak in terms of the false-alarm probability, by means of the shuffle test, and also by means of a new test (the "shake" test) that involves small random time displacements. The last two tests are the more robust, and indicate that the peak at 11.18 year(-1) would arise by chance only once out of about 10(7) trials. However, the fact that there are several peaks in the rotational search band suggests that modulation of the count rate involves several low-Q oscillations rather than a single high-Q oscillation, possibly indicative of a partly stochastic process. To pursue this possibility, we investigate the running-mean of the power spectrum, and identify a major peak at 11.93 year(-1) with peak running-mean power 4.08. Application of the shuffle test indicates that there is less than one chance in 10(11) of finding by chance a value as large as 4.08. Application of the shake test lads to a more restrictive result that there is less than one chance in 10(15) of finding by chance a value as large as 4.08. We find that there is notable agreement in the running-mean power spectra in the rotational search band formed from BNL data and from ACRIM total solar irradiance data. Since rotation rate estimates derived from irradiance data have been found to be closely related to rotation rate estimates derived from low-energy solar neutrino d