IDENTICAL BANDS IN DEFORMED AND SUPERDEFORMED NUCLEI

The observation of rotational bands in different nuclei that have unexpectedly identical moments of inertia and, sometimes, identical gamma-ray energies has excited the low-energy nuclear physics community recently. These identical bands exist at both low and high spins, and they span a wide variety of shapes that range from weakly oblate, to normal, moderately large, and super-prolate deformations. The pervasive occurrences of identical bands point to the rigidity of the even-even nuclei with respect to the polarization forces of the unpaired valence nucleons. This unexpected stability has posed a serious challenge to theoretical models.