Standard Solar Neutrinos and The Standard Solar Model

The standard solar model (SSM) yield a 8B solar neutrino flux which is consistent within the theoretical and experimental uncertainties with that observed at SuperKamiokande. The combined results from the SuperKamiokande and the Chlorine solar neutrino experiments do not provide a solid evidence for neutrino properties beyond the minimal standard electroweak model. The results from the Gallium experiments and independently the combined results from Super-Kamiokande and the Chlorine experiment imply that the 7Be solar neutrino flux is strongly suppressed compared with that predicted by the SSM. This conclusion, however, is valid only if the neutrino absorption cross sections near threshold in Gallium and Chlorine do not differ significantly from their theoretical estimates. Such a departure has not been ruled out by the Chromium source experiments in Gallium. Even if the 7Be solar neutrino flux is suppressed compared with that predicted by the SSM, still it can be due to astrophysical effects not included in the simplistic SSM. Such effects include spatial and/or temporal variations in the temperature in the solar core induced by the convective layer through g-modes or by rotational mixing in the solar core, and dense plasma effects which may strongly enhance p-capture by 7Be relative to e-capture. The new generation of solar observations, which already look non stop deep into the sun, like Super-Kamiokande through neutrinos, and SOHO and GONG through acoustic waves, may be able to point at the correct solution; astrophysical solutions if they detect unexpected temporal and/or spatial behaviour, or particle physics solutions if Super-Kamiokande detects characteristic spectral distortion or temporal variations (e.g., the day-night effect) of the 8B solar neutrino flux . If Super-Kamiokande will discover neither spectral distortions nor time dependence of the 8 solar neutrino flux then, only future solar neutrino experiments such as SNO, BOREXINO and HELLAZ, will be able to find out whether the solar neutrino problem is due to neutrino properties beyond the minimal standard electroweak model or whether it is just a problem of the too simplistic standard solar