High-spin states and superdeformation in the proton-neutron interacting boson model

The superdeformed band in ¹⁹²Hg has a similar structure to the ground-state bands in several actinide nuclei, particularly to the uranium isotopes, such as ²³²U. We report on neutron-proton Interacting Boson Model (IBM-2) calculations for the uranium isotopes and make a specific comparison of the superdeformed band in ¹⁹²Hg with the ground-state band in ²³²U. Theoretically these two bands should have the same structure in the Interacting Boson Model, because they contain the same number of active proton bosons and neutron bosons, with the superdeformed band in ¹⁹²Hg being treated as a 4p-6h excited state in terms of fermions. Results of a no new free parameter IBM-2 configuration mixing calculation for the (0p-2h), (2p-4h) and (4p-6h) configurations in ¹⁹²Hg are presented.