Determination of the neutrino mass by electron capture in 163 Holmium and the role of the three-hole states in 163 Dysprosium

Understand

163 Holmium to 163 Dysprosium is probably due to the small Q value of about 2.5 keV the best case to determine the neutrino mass by electron capture.

• The energy of the Q value is distributed between the excitation of Dysprosium (and the neglected small recoil of Holmium) and the relativistic energy of the emitted neutrino including the restmass.
• The reduction of the upper end of the deexcitation spectrum of Dysprosium below the Q value allows to determine the neutrino mass.
• The excitation of Dysprosium can be calculated in the sudden approximation of the overlap of the electron wave functions of Holmium minus the captured electron and one-, two-, three- and multiple hole-excitations in Dysprosium.