Cross Sections of Solar Neutrino Capture by Nuclei and Charge-Exchange Resonances

Abstract

The resonance structure of charge-exchange strength function S(E) and its effect on the cross sections of neutrino capture by ⁷¹Ga, ⁹⁸Mo, and ¹²⁷I were examined using the self-consistent theory of finite Fermi systems. Gamow–Teller, analog, and lower-lying pygmy resonances are considered in calculating strength function S(E). Cross sections σ(E) of solar neutrino capture are calculated for the above three isotopes with the resonance structure of strength function S(E) factored in, and the influence of each resonance on energy dependence σ(E) is analyzed. It is found that all charge-exchange resonances in strength function S(E) must be considered in calculating cross section σ(E). Even if just the high-lying resonances are neglected, cross section σ(E) can be underestimated, and this could affect the interpretation of experimental data.