Normal and superdeformed high-spin structures in $^{161}$Lu
Résumé
High-spin states in 161Lu were populated in the 139La(28Si, 6n) reaction and gamma-ray coincidences were measured with the EUROBALL spectrometer. On the basis of these data, the previously known level scheme is extended with new band structures and is partly revised. Configuration assignments are made to all bands based on comparison of experimental properties with cranked shell model calculations. A strongly populated band with parity and signature (pi,alpha)=(+,-1/2) is found to be yrast above spin I~=33. This band shows characteristics resembling those of two triaxial superdeformed bands in this nucleus based on the occupation of the shape-driving i13/2 proton orbital. This structure, unique to 161Lu within the chain of even-N Lu isotopes, is discussed in terms of a quasiparticle configuration in a local triaxial minimum with a larger triaxiality and a smaller quadrupole deformation than calculated for the i13/2 proton excitation.