Effect of High-Lying Resonances on Cross Sections for Solar-Neutrino Capture by I Nuclei

The resonance structure of the charge-exchange strength function and its effect on the cross sections for solar-neutrino capture by I nuclei are analyzed. Three types of isobaric resonances are studied within the self-consistent theory of finite Fermi systems. These are the giant Gamow–Teller resonance; the analog resonance; and the pygmy resonances, which lie lower. The capture cross section for solar neutrinos incident to I nuclei is calculated with allowance for the resonance structure of the strength function , and the effect of each resonance on the energy dependence is analyzed. It is shown that all high-lying charge-exchange resonances should be taken into account in calculating the cross section . The contributions of neutrinos of different origin to the structure of the cross section are analyzed. In particular, the contribution of energetic neutrinos to the ratio of the Xe and Xe production rates is considered. The Xe Xe isotope ratio is an indicator of hard boron neutrinos in the solar spectrum.