Emergent Collectivity in Nuclei and Enhanced Proton-Neutron Interactions

摘要

Enhanced proton-neutron interactions occur in heavy nuclei along a trajectoryof approximately equal numbers of valence protons and neutrons. This is alsoclosely aligned with the trajectory of the saturation of quadrupoledeformation. The origin of these enhanced p-n interactions is discussed interms of spatial overlaps of proton and neutron wave functions that areorbit-dependent. It is suggested for the first time that nuclear collectivityis driven by synchronized filling of protons and neutrons with orbitals havingparallel spins, identical orbital and total angular momenta projections,belonging to adjacent major shells and differing by one quantum of excitationalong the z-axis. These results may lead to a new approach to symmetry-basedtheoretical calculations for heavy nuclei.