Electron–neutrino survival probability from solar-neutrino data

Abstract

With SNO data [SNO Collaboration, nucl-ex/0106015] on electron–neutrino flux from the sun, it is possible to derive the ν e survival probability P ee ( E ) from existing experimental data of Super-Kamiokande, gallium experiments and Homestake. The combined data of SNO and Super-Kamiokande provide boron ν e flux and the total flux of all active boron neutrinos, giving thus P ee ( E ) for boron neutrinos. The Homestake detector, after subtraction of the signal from boron neutrinos, gives the flux of Be+CNO neutrinos, and P ee 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.