Atomic ionization of germanium due to neutrino magnetic moments

TL;DR

This paper presents an ab initio calculation of germanium atom ionization by neutrinos, aiming to improve the accuracy of cross section formulas for neutrino magnetic moment searches with low-threshold Ge detectors.

Contribution

It introduces a more precise atomic ionization cross section calculation using multiconfiguration relativistic RPA, surpassing the conventional free electron approximation.

Findings

The new cross section formula differs from the conventional one.

Comparison with experimental data shows improved accuracy.

Limits on neutrino magnetic moments are refined using the new method.

Abstract

An ab initio calculation of atomic ionization of germanium (Ge) by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation. The main goal is to provide a more accurate cross section formula than the conventional one, which is based on the free electron approximation, for searches of neutrino magnetic moments with Ge detectors whose threshold is reaching down to the sub-keV regime. Limits derived with both methods are compared, using reactor neutrino data taken with low threshold germanium detectors.