Discriminating MSW solutions to the solar neutrino problem with flux-independent information at SuperKamiokande and SNO

The two possible Mikheyev–Smirnov–Wolfenstein (MSW) solutions of the solar neutrino problem (one at small and the other at large mixing angle), up to now tested mainly through absolute neutrino flux measurements, require flux-independent tests both for a decisive conformation and for their discrimination. To this end, we perform a joint analysis of various flux-independent observables that can be measured at the SuperKamiokande and Sudbury Neutrino Observatory (SNO) experiments. In particular, we analyze the recent data collected at SuperKamiokande after 374 days of operation, work out the corresponding predictions for SNO, and study the interplay between SuperKamiokande and SNO observables. It is shown how, by using only flux-independent observables from SuperKamiokande and SNO, one can discriminate between the two MSW solutions and separate them from the no oscillation case.