Electron–neutrino survival probability from solar-neutrino data

With SNO data [SNO Collaboration, nucl-ex/0106015] on electron–neutrino flux from the sun, it is possible to derive the νe survival probability Pee(E) from existing experimental data of Super-Kamiokande, gallium experiments and Homestake. The combined data of SNO and Super-Kamiokande provide boron νe flux and the total flux of all active boron neutrinos, giving thus Pee(E) for boron neutrinos. The Homestake detector, after subtraction of the signal from boron neutrinos, gives the flux of Be+CNO neutrinos, and Pee for the corresponding energy interval, if the produced flux is taken from the Standard Solar Model (SSM). Gallium detectors, GALLEX, SAGE and GNO, detect additionally pp-neutrinos. The pp flux can be calculated subtracting from the gallium signal the rate due to boron, beryllium and CNO neutrinos. The ratio of the measured pp-neutrino flux to that predicted by the SSM gives the survival probability for pp-neutrinos. Comparison with theoretical survival probabilities shows that the best (among known models) fit is given by LMA and LOW solutions.