Parity-doublet bands in pear-shaped nucleus ^ 145Ba

The spontaneous breaking of the space reflection symmetry occurs in nuclei with octupole deformations (such as pear shape), which has attracted a lot of attention in nuclear physics.The possible two pairs of parity doublet bands observed in neutron-rich odd-mass nucleus ^145Ba are investigated using the reflection-asymmetric triaxial particle-rotor model.The experimental energy spectra, energy staggering parameters, and the B(E1)/B(E2) ratios are well reproduced by the theoretical calculations.The detailed analysis of the intrinsic wave functions shows that the main components of the parity doublet bands based on 5/2^- ground state and 9/2^+ excited state (with the excitation energy of 507.4 keV) are ν h_9/2f_7/2⊕ i_13/2 (Ω=3/2) and ν i_13/2p_3/2⊕ g_9/2 (Ω=1/2), respectively.By analyzing the variation of these main components with spin, the signature splitting behavior for the parity doublet bands can be understood.