High spin states in 164Lu.

Abstract

High spin states in the odd-odd $^{164}\mathrm{Lu}$ nucleus have been investigated for the first time, through in-beam gamma-ray spectroscopy, following the $^{150}\mathrm{Sm}$${(}^{19}$F,5n) reaction at beam energy ${\mathit{E}}_{\mathrm{lab}}$=105 MeV. Four bands, including two signature split bands are identified. The interpretation of the experimental results is discussed in comparison with the existing data in the neighboring nuclei and in the framework of the cranked shell model. The \ensuremath{\pi}${\mathit{h}}_{11/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{i}}_{13/2}$ yrast band exhibits anomalous signature splitting and signature inversion is observed at a spin of 18\ensuremath{\Elzxh}. This provides the missing datum for the systematics of staggering and signature inversion for the neighboring odd-odd N=93 isotones and supports the predictions of angular-momentum projection calculations by Hara and Sun. In the second signature split \ensuremath{\pi}h $_{11/2}\mathit{h}_{9/2}$ band, the AB neutron crossing occurs at a rotational frequency of \ensuremath{\sim}0.29 MeV. This is indicative of the disappearance of the blocking effect of the odd neutron.