The experimental determination of the solar neutrino flux (Homestake G
oldmine, GALLEX and SAGE, Kamiokande and Super-Kamiokande) show a defi
cit compared to what is predicted by the standard solar model can be d
ue to either the experimental data and the theoretical results of the
standard solar model can be due either to defects in the solar model o
r to neutrino properties. (C) Academie des Sciences/Elsevier, Paris.