EXCITED-STATES IN SM-139 DESCRIBED WITH THE INTERACTING BOSON MODEL PLUS BROKEN PAIRS

The high-spin structure of Sm-139 has been studied through the Pd-110( S-34,5n) reaction at beam energies of 150 and 165 MeV. The level schem e has been extended up to an excitation energy of 11.1 MeV and spin 61 /2(+). A band built on the vi(13/2) [660]1/2(+) intruder orbital has b een established and firmly linked to the known lower-spin levels in th e nucleus. The low-lying states of both parities as well asa relativel y strong Delta I=1 regular structure observed above spin 27/2(-) are n icely reproduced by the interacting boson-fermion model with broken pa irs.