Anomalous Signature Splitting of the πh_11/2 vi_13/2 Band in A ～ 160 Odd-Odd Nuclei

Systematic features of anomalous signature splitting of the πh_11/2 vi_13/2 band in A ～ 160 odd-odd nuclei have been investigated. It is shown that the mechanism of anomalous signature splitting is similar to that of the normal signature splitting which is essentially caused by the Coriolis mixing of Ω = 1/2 components into the nuclear wave function and the anomalous splitting in signature is mainly caused by the definition. The extensively observed anomalous signature splitting in this band might be an indication that the interaction between the h_11/2 proton and the i_13/2 neutron can not be neglected. The new observation of high- and low-K bands based on the same πh_11/2 vi_13/2 configuration in ¹⁶⁴Tm is also discussed.