Interacting Boson Model plus broken-pairs description of high-spin dipole bands

The Interacting Boson Model with broken-pairs has been extended to include mixed proton-neutron configurations in the fermion model space. The extended version of the model has been used to describe high-spin bands in the transitional nucleus $^{136}$Nd. Model calculations reproduce ten bands of positive and negative parity states, including the two dipole high-spin structures based on the $(pi h_{11/2})^2$ $( u h_{11/2})^2$ configuration.