A Model Independent Analysis of Solar Neutrino Data

We present the results of a solar model independent analysis of the existing solar neutrino data in the case of $\nu_{e}\to\nu_{\mu(\tau)}$ MSW transitions. We considered two cases. In the first case no assumptions on the values of the total fluxes of neutrinos from all reactions have been made. In the second case we constrained the values of the neutrino fluxes within some wide limits that take into account the predictions of the existing Standard Solar Models. We show that in both cases the existing data allow to exclude rather large regions in the plane of the parameters $\Delta m^2$ and $\sin^2 2\theta$.