Rotational signature and possible r-mode signature in the GALLEX solar neutrino data

Recent analysis of the Homestake data has yielded evidence that the solar n eutrino flux varies in time-more specifically, that it exhibits 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. Her e we present a spectral analysis of the GALLEX data that yields supporting evidence for this rotational modulation. The most prominent peak in the pow er spectrum occurs at the synodic frequency of 13.08 yr(-1) (cycles per yea r) and is estimated to be significant at the 0.1% level. It appears that th e most likely interpretation of this modulation is that the electron neutri nos have nonzero magnetic moment, so that they oscillate between left-hand (detectable) and right-hand (nondetectable) chiralities as they traverse th e Sun's internal magnetic field. This oscillation could account for the neu trino deficit. The second strongest peak in the GALLEX spectrum has a perio d of 52 days, and this period occurs in other solar data as well. We sugges t that this periodicity and also the Rieger 154 day periodicity, which show s up in many solar parameters and in the Homestake data, are due to r-mode oscillations.