Magnetic moment solution to the solar neutrino problem, anticorrelation with sunspot activity and challenges for future experiments

The analysis of the most recent solar neutrino data in the light of the resonant spin flip flavour conversion of neutrinos in the Sun suggests the existence of two possible solutions for the solar neutrino problem, one of them associated with a neutrino flavour mass square difference of the order of 10-8 eV2 and the other of the order of 10-5 eV2. The magnetic moment is in the range μν =(10-12-10-11) μB. In the first possibility the most energetic neutrinos will have their resonance in the solar convective zone. This indicates that the forthcoming SNO and Icarus experiments are very well placed to test this solution through the anticorrelation effect with sunspot activity that may be present in the Homestake data but still remains an open question. (orig.). With 4 figs., 2 tabs