Testing neutrino magnetic moment in ionization of atoms by neutrino impact

TL;DR

This paper analyzes atomic ionization caused by neutrino scattering, emphasizing the importance of accurate theoretical models for interpreting neutrino magnetic moment experiments with germanium detectors.

Contribution

It demonstrates the applicability of the stepping approximation for neutrino-impact ionization of atoms, especially for low bound states, and provides numerical evidence using the Thomas-Fermi model.

Findings

Stepping approximation is valid for lowest bound Coulomb states.

The approximation becomes exact in the semiclassical limit.

Numerical analysis supports the theoretical model.

Abstract

The atomic ionization processes induced by scattering of neutrinos play key roles in the experimental searches for a neutrino magnetic moment. Current experiments with reactor (anti)neutrinos employ germanium detectors having energy threshold comparable to typical binding energies of atomic electrons, which fact must be taken into account in the interpretation of the data. Our theoretical analysis shows that the so-called stepping approximation to the neutrino-impact ionization is well applicable for the lowest bound Coulomb states, and it becomes exact in the semiclassical limit. Numerical evidence is presented using the Thomas-Fermi model for the germanium atom.