Y. Z. Liu

Evolution of the X(5) critical-point symmetry in rotating \mathrm{\mathbf {^{176}Os}}

Lifetimes of excited states above 10+ in the yrast band in 176Os have been measured using the Doppler shift attenuation method, via the fusion evaporation reaction . Lifetimes of states over 12+ were measured for the first time. The deduced transitional quadruple moments (Qt), together with the previous data using a recoil distance method, are compared with theoretical calculations based on the X(5) model and the interaction boson model. For the states below spin 10+, the data of previous work support an X(5)-like structure, but for the states above 10+, the value of Qt remains almost constant, being the characteristic of a symmetric rotor. The present result suggests that the shape of the nucleus 176Os changes from X(5) critical-point symmetry to an axially deformed rotor with increasing spin.

First identification of high-spin states in Ta

The yrast band in at high-spin states is established for the first time through the reaction at a beam energy of 127 MeV. Excitation function, residual radioactivity, and , coincidences were measured. Signature inversion features of and neighbouring isotones are discussed.

Low-spin signature inversion in

The level scheme with spin up to I = 26 in the yrast band in is reported and low-spin signature inversion with the inversion point at is observed in this band. In the chain of Lu doubly-odd isotopes, with increasing neutron number, the low-spin staggering magnitude of signature dependence decreases and, at the same time, the inversion point shifts to lower spin.