Status and prospects of MSW and vacuum oscillation solutions of the solar neutrino problem

The current interpretation of the solar neutrino problem in terms of MSW or vacuum oscillations depends signiicantly on the absolute neutrino uxes, i.e., on solar model calculations. However, second-generation experiments such as SuperKamiokande, SNO, and Borexino, will be able to test these neutrino oscillation solutions independently of solar models. We discuss the theoretical estimates and the likely experimental uncertainties of several model-independent observables that can provide unmistakable signals of neutrino oscillations.