Mixed-symmetry states in the neutron-proton interacting boson model

Abstract

States of mixed proton-neutron symmetry are investigated in different dynamical symmetries of the interacting boson model. We discuss in each of the limits the energy spectrum, the wave functions and the B( M1; 0 1 + → 1 1 + ) values. We also study three classes of transitional nuclei namely the Pd nuclei [ U(5) → O(6)], the Sm nuclei [ U(5) → SU(3)] and the Pt nuclei [ O(6) → SU(3)] with respect to the energy of the lowest non-symmetric J π = 1 +, 3 + levels as well as the M1 and M3 strengths for exciting these levels from the ground state. For 98Pd we compare this calculation with a shell-model calculation. Finally, we adress the problem of the mixing of the non-symmetric J π = 1 + state with nearby hexadecapole (g-boson) configurations.