Rotational Signature and Possible R-Mode Signature in the GALLEX Solar Neutrino Data

Abstract

Recent analysis of the Homestake data indicates that the solar neutrino flux contains a periodic variation that may be attributed to rotational modulation occurring deep in the solar interior, either in the tachocline or in the radiative zone. This paper presents an analysis of GALLEX data that yields supporting evidence of this rotational modulation at the 0.1% significance level. The depth of modulation inferred from the rotational signature is large enough to explain the neutrino deficit. The Rieger 157-day periodicity, first discovered in solar gamma-ray flares, is present also in Homestake data. A related oscillation with period 52 days is found in the GALLEX data. The relationship of these periods to the rotational period inferred from neutrino data suggests that they are due to r-mode oscillations.