Neutrino-impact ionization of atoms in searches for neutrino magnetic moment

Understand

The ionization of atomic electrons by scattering of neutrinos is revisited.

• This process is the one studied in the experimental searches for a neutrino magnetic moment using germanium detectors.
• Current experiments are sensitive to the ionization energy comparable with the atomic energies, and the effects of the electron binding should be taken into account.
• We find that the so-called stepping approximation to the neutrino-impact ionization is in fact exact in the semiclassical limit and also that the deviations from this approximation are very small already for the lowest bound Coulomb states.