  The Super-Kamiokande best global fit, which includes data from SNO, Gallium
and Chlorine experiments, results in a hep neutrino contribution to the signals
that, even after oscillation, is greater than the SSM prediction. The solar hep
neutrino flux that would yield this contribution is four times larger than the
one predicted by the SSM. Recent detailed calculations exclude that the
astrophysical factor S_{hep}(0) could be wrong by such a large factor. Given
the reliability of the temperature and densities profiles inside the Sun, this
experimental result indicates that plasma effects are important for this
reaction. We show that a slight enhancement of the high-energy tail,
enhancement that is of the order of the deviations from the Maxwell-Boltzmann
distribution expected in the solar core plasma, produces an increment of the
hep rate of the magnitude required. We verified that the other neutrino fluxes
remain compatible with experimental signals and SSM predictions. Better
measurements of the high-energy tail of the neutrino spectrum would improve our
understanding of reaction rates in the solar plasma.

High Energy Physics - Phenomenology