  Theoretical models which present flavor changing neutrino interactions and
simultaneously prevent this particle from acquiring any mass exist. We discuss
some of them and their predictions for neutrino oscillations in matter which
can account for the solar neutrino anomaly as well as the zenith-angle
dependence of the deficit of atmospheric neutrinos observed by the
SuperKamiokande experiment without invoking, therefore, neutrino masses nor
mixing.

High Energy Physics - Phenomenology