Excited states in ${}_{}{}^{139}{}_{}{}^{}\mathrm{Sm}$ described with the interacting boson model plus broken pairs

The high-spin structure of ${}_{}{}^{139}{}_{}{}^{}\mathrm{Sm}$ has been studied through the ${}_{}{}^{110}{}_{}{}^{}\mathrm{Pd}$${(}^{34}$S,5n) reaction at beam energies of 150 and 165 MeV. The level scheme has been extended up to an excitation energy of 11.1 MeV and spin 61/$2^{+}$. A band built on the ν${\mathit{i}}_{13/2}$ [660]1/$2^{+}$ intruder orbital has been established and firmly linked to the known lower-spin levels in the nucleus. The low-lying states of both parities as well as a relatively strong ΔI=1 regular structure observed above spin 27/$2^{\mathrm{-}}$ are nicely reproduced by the interacting boson-fermion model with broken pairs. © 1996 The American Physical Society.