Resonances in the solar neutrino capture cross-section for $ ^{76}Ge $ nuclei

TL;DR

This paper calculates the solar neutrino capture cross-section for $^{76}Ge$, highlighting the significant role of resonant structures, especially the giant Gamow-Teller resonance, in background event estimation for double beta decay experiments.

Contribution

It introduces a method to incorporate resonant structures of the strength function into cross-section calculations for $^{76}Ge$ solar neutrino capture.

Findings

Giant Gamow-Teller resonance contributes about 20% to the cross-section.

Excited states below the resonance significantly affect the cross-section.

Resonant structures must be considered in background estimations for double beta decay experiments.

Abstract

The calculation results of solar neutrino capture cross-section on the $^{76}Ge$ nucleus are presented. The charge-exchange strength function $S(E)$ was obtained from the experiment data in the $ ^{76}Ge(^{3}He, t)^{76}As $ reaction. The calculation includes the effect of the resonant structure of the strength function $S(E)$ on the calculated cross section $\sigma(E_{\nu})$. It is shown that only the giant Gamow-Teller resonance contributes about 20%, and an even greater contribution is made by excited states located lower in the continuous part of the spectrum. These contributions should be taken into account in the calculation of background events in experiments on double beta decay of the GERDA type (for example LEGEND).