QUASI-PERIODIC VARIATION IN THE SOLAR-NEUTRINO FLUX REVISITED

Neutrino capture rate data from the Homestake chlorine experiment (197 0-1990) has been spectrally analysed. The data were smoothed by a 4-mo nth equally-spaced sequence and by a cubic spline polynomial approxima tion. Fourier (FFT), maximum entropy spectrum analysis (MESA), and pow er spectrum analysis (PSA) employing the Blackman-Tukey window were us ed. The significant periodicities obtained are: 1 +/- 0.1, 1.4 +/- 0.2 , 2.4 +/- 0.2, 5 +/- 0.2, and 11 +/- 1.5 years. A possible correlation with similar coincident periods in other solar-terrestrial phenomena is discussed.