Comparative Analysis of GALLEX-GNO Solar Neutrino Data and SOHO/MDI Helioseismology Data; Further Evidence for Rotational Modulation of the Solar Neutrino Flux
We carry out a comparative analysis of the GALLEX-GNO solar neutrino data and estimates of the solar internal rotation rate derived from the MDI helioseismology experiment on the SOHO spacecraft. We introduce a statistic, which we evaluate as a function of radius and latitude, that is a measure of the degree of "resonance" of oscillations in the neutrino flux and the synodic solar rotation rate at that radius and latitude. A map of this statistic indicates that the probable location is deep in the convection zone near the equator. We also examine the integral of this statistic over the equatorial section of the convection zone. This provides a measure of the likelihood that the variability of the solar neutrino flux, as measured by the GALLEX-GNO data, has its origin in the equatorial section of the convection zone. We apply the shuffle test, randomly reassigning measurements among runs, to estimate the significance of the value of the statistic computed from the actual data. This test implies that the result is significant at the 0.2% level. When, for comparison, we repeat this analysis for the radiative zone, we find that the integral resonance statistic is not significant. These results support earlier evidence for rotational modulation of the solar neutrino flux.