On sensitivity of neutrino-helium ionizing collisions to neutrino magnetic moments

We consider theoretically ionization of a helium atom by impact of an electron antineutrino. The sensitivity of this process to neutrino magnetic moments is analyzed. In contrast to the recent theoretical prediction, no considerable enhancement of the electromagnetic contribution with respect to the free-electron case is found. The stepping approximation is shown to be well applicable practically down to the ionization threshold.