Partial dynamical symmetries and prolate-oblate coexistence in nuclei

We present a symmetry-based approach for describing prolate-oblate and spherical-prolate oblate shape coexistence in nuclei. The proposed number-conserving rotational-invariant bosonic Hamiltonian involves three-body terms. It preserves two different variants of SU(3) symmetry for the prolate and oblate ground bands and the U(5) symmetry for selected spherical states. Quadrupole moments and B(E2) transition rates, involving these states, are calculated in closed form and isomeric states are identified by means of selection rules. The purity of particular subsets of states, in the presence of other mixed states, demonstrates the relevance of partial dynamical symmetries to shape-coexistence in nuclei. This document is composed of an abstract and the slides of the presentation. (author)