Neutrino Potential for Neutrinoless Double Beta Decay

Nuclear matrix element in double beta decay under the closure approximation is outlined, in which neutrino potential for neutrinoless double beta decay is studied with focusing on its statistical property. It is shown from the analysis that Fermi and Gamow-Teller parts provide almost the same positive values with the Fermi part slightly larger than the Gamow-Teller part in general, while the tensor part includes small but non-negligible positive and negative values. Positive correlation of the values between Fermi, Gamow-Teller, and tensor parts has been clarified. The statistics provides a gross view of understanding amplitude of constitutional components of the nuclear matrix element.