Long-wavelength oscillations and the new gallium solar neutrino signals

The recently reported solar neutrino signal in the 71 Ga GALLEX detector adds a new dimension to the solar neutrino puzzle, complementing the previously known signals in 37 Cl and water-Cherenkov detectors. Possible explanations for this new signal in terms of matter-enhanced neutrino oscillations (MSW effect) are already awaiting in the literature. We point out here that long-wavelength vacuum oscillations can furnish an alternative explanation of all three signals simultaneously; such solutions give neutrino spectra with distinctive energy dependence and seasonal time dependence.