Partial dynamical SU(3) symmetry and the nature of the lowest K=0 collective excitation in deformed nuclei - art. no. 061301

We discuss the implications of partial dynamical SU(3) symmetry (PDS) for t he structure of the lowest K = 0(+)(K=0(2)) collective excitation in deform ed nuclei. We consider an interacting boson model Hamiltonian whose ground and gamma bands have good SU(3) symmetry, while the K=0(2) band is mixed. I t is shown that the double-phonon components in the K=02 wave function aris e from SU(3) admixtures which, in turn, can be determined from absolute E2 rates connecting the K=0(2) and ground bands. An explicit expression is der ived for these admixtures in terms of the ratio of K=0(2) and gamma bandhea d energies. The SU(3) PDS predictions are compared with existing data and w ith broken-SU(3) calculations for Er-168. [S0556-2813(99)50711-5].