We discuss the results of Homestake and Kamioka experiments, showing that - if the results of these experiments are taken at their face values - one way to save "conventional neutrinos" is to look for a nuclear solution decreasing both 7Be and 8B neutrino fluxes with respect to the predictions of the standard solar models. Recent GALLEX results appear in agreement with such a conclusion. We discuss the sensitivity of the 8B and 7Be neutrino fluxes to the behaviour of the low energy 3He+3He and 3He + 4He cross sections. We derive analytically the dependence of the neutrino fluxes on the low energy nuclear cross sections. This analytical approach has been supported by numerical experiments based on a new Standard Solar Model. In the non-resonant case, reduction of the neutrino fluxes to about 1/3 of the Standard Solar Model could be obtained if the true value of S34(0) is three times smaller than the presently accepted extrapolated value. Alternatively, one should have S33(0) wrong by a factor nine. A resonance in the 3He + 3He channel could yield a sufficient reduction of 8B neutrinos and, furthermore, a suppression of 7Be neutrinos larger than that of 8B neutrinos provided that ER ≤ 21.4 keV. an energy region so far almost unexplored experimentally. We show that future experiments in underground laboratories should be able to explore the region down to ER = 10 keV with a significant sensitivity. We also compare our Standard Solar Model with the results of previous calculations.
SOLAR NEUTRINOS AND NUCLEAR-REACTIONS IN THE SOLAR INTERIOR
FIORENTINI, Giovanni
1993
Abstract
We discuss the results of Homestake and Kamioka experiments, showing that - if the results of these experiments are taken at their face values - one way to save "conventional neutrinos" is to look for a nuclear solution decreasing both 7Be and 8B neutrino fluxes with respect to the predictions of the standard solar models. Recent GALLEX results appear in agreement with such a conclusion. We discuss the sensitivity of the 8B and 7Be neutrino fluxes to the behaviour of the low energy 3He+3He and 3He + 4He cross sections. We derive analytically the dependence of the neutrino fluxes on the low energy nuclear cross sections. This analytical approach has been supported by numerical experiments based on a new Standard Solar Model. In the non-resonant case, reduction of the neutrino fluxes to about 1/3 of the Standard Solar Model could be obtained if the true value of S34(0) is three times smaller than the presently accepted extrapolated value. Alternatively, one should have S33(0) wrong by a factor nine. A resonance in the 3He + 3He channel could yield a sufficient reduction of 8B neutrinos and, furthermore, a suppression of 7Be neutrinos larger than that of 8B neutrinos provided that ER ≤ 21.4 keV. an energy region so far almost unexplored experimentally. We show that future experiments in underground laboratories should be able to explore the region down to ER = 10 keV with a significant sensitivity. We also compare our Standard Solar Model with the results of previous calculations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
