Interacting boson fermion-fermion model calculation of theπh11∕2⊗νh11∕2doublet bands inPr134

Abstract

The interacting boson fermion-fermion model is employed in the analysis of the positive-parity doublet bands in $^{134}\mathrm{Pr}$. It is shown that stable triaxial deformation gives rise to the experimentally observed crossing between the yrast and yrare bands built on the $\ensuremath{\pi}{h}_{11∕2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11∕2}$ configuration. The collective structure of the yrast band is basically built on the ground-state band of the triaxial core, whereas the collective structure of the yrare band is predominantly based on the $\ensuremath{\gamma}$ band of the core. The mixing between the two bands increases with angular momentum. A constant energy spacing between the two lowest positive-parity bands is predicted in other odd-odd $N=75$ nuclei with $\ensuremath{\gamma}$-soft potential energy surfaces.