Neutron excitations and interactions above the N=80 superdeformed closed shell: Superdeformation in 144Eu

Three superdeformed bands have been observed in the nucleus 144Eu with the GAMMASPHERE spectrometer in its early implementation phase. The reaction used was 122Sn(27Al,5n)144Eu at a beam energy of 142 MeV. All three bands are identified as single-neutron excitations with respect to 143Eu. One band is a confirmation of a previously suggested candidate. It is assigned as the yrast sequence based on the π61ν71 configuration, and is believed to undergo an interaction with the ν[514]9/2- orbital. The other two bands are assigned as signature partners based on the π61ν6̃1 configuration, where 6̃ corresponds to a mixed [651]1/2+/ [642]5/2+ state. The partner that contains the α=-1/2 signature component of the 6̃ orbital is identified from a band crossing that occurs in related bands in 145Gd and 146Gd. Alignment plots suggest that the interaction strength becomes stronger as the mass number increases.