Pseudo-spin band in the odd-odd nucleus ~(172)Lu

摘要

High-spin states in the odd-odd nucleus ~(172)Lu have been populated in a ~(170)Er(~7Li,5n) reaction and the emitted γ-radiation was detected with the GASP array. Two sequences of a new identical band have been observed wit the transition energies in the favoured and unfavoured sequences being identical within ≈ 3 keV at low spins and ≈ 1 keV at high spins over the hole observed spin range. An interpretation as a pseudo-spin single band of π1/2~-[541] direct X v1/2~-[420]-tilde configuration is proposed. It represents the best example of a pseudo-spin singlet band in normal deformed nuclei known until now.