Neutron-proton interaction in odd-odd nuclei from statistical analysis

Abstract

The statistical distribution and correlation relationship of the empirical neutron-proton ($np$) interaction are analyzed, whereby the interaction strengths are extracted from the binding energies using a known four-point formula. By comparing the correlations of the data and those from numerical simulations of the random number method, it is shown that an additional attractive $np$ interaction persists between the last proton and last neutron in odd-odd nuclei. It provides evidence of the residual $np$ interaction from statistical analysis. The adopted new analytical method might be a useful way to clarify the inherent correlation.