Unknowns after the SNO Charged-Current Measurement

We perform a model-independent analysis of solar neutrino flux rates including the recent charged-current measurement at the Sudbury Neutrino Observatory (SNO). We derive a universal sum rule involving SNO and SuperKamiokande rates, and show that the SNO neutral-current measurement can only fix the fraction of solar $\nu_e$ oscillating to sterile neutrinos if the $^8$B neutrino flux normalization is assumed to be known. Imposing adiabatic constraints do give an unique solution for the sterile neutrino fraction, but the uncertainties are large.