Wang Shou-Yu

Observation of Three-Quasiparticle Doublet Bands in 123I: Possible Evidence of Chirality

A new band in the odd proton nucleus 123I is identified via in-beam γ-ray spectroscopy using the 14N+116Cd reaction. This band shows up as doublets with the previously assigned πg7/2 ⊗ (νh11/2)2 band. Possible configurations of the new band are discussed in the framework of the cranked shell model and the geometrical model. It is argued that the new band might be a chiral partner of the previously known πg7/2 ⊗ (νh11/2) band.

Coupling Parameter in the Single-j Shell Model

We propose a modified formula which is used to determine the coupling parameter.. in the Hamiltonian of the single-j shell. In comparison with the previously known formula, the new formula improves the agreement between the intruder single-j levels and the Nilsson ones. For studies of chiral bands within the particle rotor model, the new coupling parameter will considerably influence the energy splitting between the doublet bands.

Band Interaction between Chiral Doublet Bands

Band interaction between the chiral doublet bands based on πh11/2 ⊗ vh−111/2 configuration is investigated in the particle rotor model with different triaxial deformation γ. The variation of chiral partner states with γ values is understood qualitatively based on the basic picture of two interaction levels, which is confirmed further by the calculated overlap integral of wave functions at different γ values. It is found that the interaction strengths of chiral partner states are obviously different for odd spins and even ones.

Band Structures of the Nucleus 129Cs

High-spin states in 129Cs are populated via the 122Sn (11B, 4n) reaction at beam energies of 55 and 60 MeV. Two additional bands are placed in the level scheme and the previously known bands are extended to higher spins. The results are compared to the cranked shell model calculations and to the systematics of the adjacent Cs isotpoes. One of the new bands is interpreted as the γ-vibrational band built on the πh11/2 orbital. The possible configuration for another new band is discussed. Upbend caused by (vh11/2)2 alignment is observed both in the favored and unfavored sequences of the πh11/2 configuration. The band based on the πg7/2 configuration at low spins forks around spin 17/2, and the two different S-bands are attributed to (vh11/2) and (πh11/2)2 rotational alignments, respectively.

Transition from Electric Rotation to Chiral Mode in 135Nd

With the inputs from the relativistic mean field approach, the observed energy spectra and electromagnetic properties are well reproduced for the yrast band of odd-A nucleus 135Nd by the particle rotor model. Based on the analysis of the angular momentum components, it is further illustrated that this yrast band contains two stages of rotational mode, i.e., the electric rotation for low-spin region and chiral mode for high-spin region.

Chiral Doublet Bands with νh11/2 ⊗ νd−15/2 Configuration in the Particle Rotor Model

Doublet bands with νh11/2⊗νd−15/2 configuration are studied for the first time via the triaxial particle rotor model. The main properties of the doublet bands, including the energy spectra and the electromagnetic transitions, are presented for different triaxiality parameter γ. The aplanar rotation and chiral geometry are discussed based on the analysis of angular momentum components.

Structural evolution of the intruder band in 118 Sn

Excited states of the positive-parity intruder band in 118Sn have been studied via the 116Cd(7Li, 1p4n) reaction at 7Li energy of 48 MeV using techniques of in-beam γ-ray spectroscopy. This intruder band has been observed up to 7187 keV with spin (16+). The structural evolution of this intruder band with increasing angular momentum has been discussed in terms of the aligned angular momentum and the ratio of the E-Gamma Over Spin (E-GOS) curve.

The Influence of Triaxiality Parameter γ on the Chiral Doublet Bands with (πg9/2)−1 (νh11/2)2 Configuration

The chiral doublet bands with three-quasiparticle configuration (πg9/2)−1 (νh11/2)2 are studied by the fully quantal triaxial particle rotor model. The energy spectra and B(M1)/B(E2) ratios of the doublet bands with different triaxiality parameter γ are systematically analyzed. It is found that γ is a sensitive parameter for the properties of these doublet bands.

πg9/2⊗vh11/2doublet bands in A ∼ 100 mass region

Using the model with one particle and one hole coupled with a triaxial rotor, the πg9/2−1 ⊗vh11/2 doublet bands in the A ~ 100 mass region are studied, and compared with the πh11/2−1 ⊗vh11/2 doublet bands. It is found that the calculated results for the configuration of πg9/2−1 ⊗vh11/2 are very similar the results for a pure h11/2 proton particle and a neutron quasiparticle with λn = 5. After including the pair correlation, the model describes the candidate chiral doublet bands in 106Rh successfully, which supports the interpretation of chirality geometry.

Structure change of (156)Yb at high-spin states

National Natural Science Foundation of China[10405001, 10775005, 10735010, 10605001, J0730316]; Chinese Major State Basin Research Development Program[2007CB815002]