Speaker
Piet Van Isacker
Description
Nuclei with a closed-shell configuration for neutrons and protons exhibit low-energy excitations with angular momentum J=3 and negative parity. Such excitations are associated with nuclear shapes that break reflection symmetry and, in particular, with pear-like or octupole shapes. In this talk the symmetry structure of octupole excitations is discussed and the question of their phonon-like behaviour is addressed. It is shown that with some simple assumptions concerning single-particle energies and nucleonic interactions octupole excitations obey universal symmetry properties. The results of this schematic approach are compared with those of a realistic shell-model calculation for 208Pb. An extension to odd-mass is also discussed.
Author
Piet Van Isacker
