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.
