Symmetry character of bands in Kr72-84 in the proton-neutron interacting boson model - art. no. 044302

The positive-parity bands observed in the even Kr72-84 isotopes have been s tudied in the framework of the IBA-2 model. The analysis includes states of spin up to the maximum allowed by the finite boson number. The symmetry ch aracter of these bands in the proton and neutron degrees of freedom has bee n investigated. Excitation energies, B(E2)'s of intraband transitions and B (E2)'s, B(Ml)'s, E2/M1 mixing ratios of interband transitions have been con sidered. Three bands of different structure can be accounted for in the fra mework of the model: the ground-state band, of predominant full-symmetry ch aracter; the band built on the 2(2)(+) state, which is composed by states w hich show different symmetry character along the isotopic chain; and the ba nd built on the 3(1)(+) state, of predominant mixed-symmetry character.