Description of Superdeformed Bands of the Nuclei in A ～60 Mass Region

Using the supersymmetry scheme including many-body interactions, we investigate the superdeformed (SD) bands of the nuclei in A ～ 60 mass region systematically. Quantitatively good results of the γ-ray energy spectra and the dynamical moments of inertia are obtained. It shows that the supersymmetry approach is powerful to describe the generic rotational property of SD states of light nuclei.     

Evidence for a Possible E（5） Symmetry in ^130Xe

By analysing the energy spectrum and E2 transition branching ratios,we show that the E(5) symmetry predictions agree well with the experimental data of nucleus 130Xe,Compared the calculated results with those within the framework of the interacting boson model.It is found that the nucleus 130Xe is definitely a nucleus in the transitional region from U(5) to O(6) symmetry,130Xe is then another empirical evidence of the nucleus with E(5) symmetry.     

Effect of Conversion Process （≡^－P→AA） in ≡－－Hypernuclei

Effect of conversion process (≡^-P→AA) on ≡--hypernucleus is studied for ≡^12-Be. It is found that the conversion process has a certain extent effect on properties of low-lying states of the ≡^--hypernuclei.     

Exploration of Pseudospin Symmetry in the Resonant States

Taking ^120Sn as an example, we discuss the pseudospin symmetry in the single proton resonant states by examining the energies, widths and the wavefunctions. The information of the single proton resonant states in spherical nuclei are extracted from an analytic continuation in the coupling constant method within the framework of the self-consistent relativistic mean field theory under the relativistic boundary condition. We find small energy splitting in a pair of pseudospin partners in the resonant states. The lower components of the Dirac wavefunctions of a pseudospin doublet agree well in the region where nuclear potential dominates. It is concluded that the pseudospin symmetry is also well conserved for the resonant states in realistic nuclei.     

Empirical Example of Nucleus with Transitional Dynamical Symmetry X（5）

By analysing the energy spectrum,E2 transition rates and branching ratios,it is shown explicitly that the nucleus ^150Nd provides an empirical example with X(5) symmetry at the critical point of the transition from U(5) to SU(3) symmetry.     

Properties of the Alpha Decay Chain Nuclei of ^310 126, ^292 120 and ^298 114

The properties of the a decay nuclei of^310 126, ^292 120 and ^298 114 are investigated in the deformed relativistic meanfield model. The nuclear properties are investigated with the TMA and NL-Z2 parameter sets, and compared with Moller‘s result [At. Data Nucl. Data Tables 59 (1995) 185]. The results show that the a decay energy increases systematically with the increasing proton number. Meanwhile, the a decay energy has a minimum value at the point of shell closure. It is also found that among the three nuclei, ^292 120 is more possible to be the next doubly magic nucleus.     

Description of the shape evolution in the yrast states of ~（186）Pt

^186Pt was tested in the framework of IBM-1 and the X（3） model. The results show that ^186Pt is located close to the shape phase transition point, but the B（E2） values little agree with the X（3） model. The shape evolution in the yrast states of186Pt is also discussed in detail. TRS calculation exhibits a flat bottomed potential at low spin states, but a relatively deep minimum at high spin states. It suggests that a shape evolution from vibrational mode to rotational mode happens in ^186Pt. The result is in agreement with the E-GOS calculation.     

Systematic Properties of the 1／2[660]^i13／2 Bands in Odd-A Au Nuclei

A standard in-beam γ-spectroscopy experiment for^179 Au has been performed via the ^149Sm (^35Cl, 5n) reaction at beam energies of 164-180 MeV. Based on the analysis of the experimental results, a rotational band built on 1/2[660](π^i13/2)proton intruder orbital is established for^179 Au for the first time. Systematic properties of the 1/2[660](π^i13/2) band in odd-A Au nuclei are discussed,and the evolution of bandhead energy and deformation with changing neutron number are revealed.     

Calculation of Energy Levels of Nucleus ^127I in the Particle-Triaxial-Rotor Model

Theoretical calculations have been performed for nucleus ^127I in the framework of the particle-triaxial-rotor model.The calculated results indicate that both the 5^ /2 and 7^ /2 bands are oblate deformed bands.Their comfigurations are associated with the πd5/2[402]5/2 and πg7/2[404]7/2 orbitals and the strong mixing between them.Meanwhile a possible explanation of the strong mixing is given.     

Description of Superdeformed Bands of the Nuclei in A—80 Mass Region

Within the supersymmetry scheme inchuding many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry,the superdeformed (SD) bands of the nuclei in the A-80 mass region are investigated systematically.Quantitatively good results of the γ-ray energy spectra and the dynamical monents of inertia are obtained.It is shown that the supersymmetry approach is powerful to describe not only the generic rotational property,but also the characteristic of the triaxial SD band simultaneously.     

Rotation Driven Shape-Phase Transition of the Yrast Nuclear States with O（6） Symmetry in the Interacting Boson Model

In a framework of the interacting boson model (usually referred to as IBM-1) with angular momentum projection on the coherent state, we obtain the energy surface functional of nuclei in terms of angular momentum and shape parameters. Analysing the rotation driven effect on the equilibrium shape shows that the yrast states of the nuclei with 0(6) symmetry will experience a shape-phase transition from γ-soft deformed to triaxially deformed and then to spherical shape along the yrast line as the angular momentum increases.     

Charged Pion Form Factor Determination in the Range of Q^2= 0.6-1.6 （GeV／c）^2

Using the most recent differential cross section data for e-p quasi-elastic scattering, the charged pion formation and its form factor Fπ is calculated in the energy range of 2.4-4 GeV at Q^2 = 0.6-1.6 (GeV/c)^2. The functional dependence of the charged pion form factor to the separated cross section aL is investigated and compared to the previously determined result.     

Study on Production of Exotic 0^＋ Meson D＇^＊aj（2317） in Decays of ψ（4415）

The newly observed D^＊aj family containing D^＊aj（2317）, Daj（2460）, and Daj（2632） attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model （the harmonic oscillator model） to evaluate the production rate of D^＊aj （2317） from the decays of ψ（4415）. For a comparison, we a/so employ the widely adopted heavy quark effective theory to repeat the calculation. We lind that the rate is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of Da（1968）. Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.     

Microscopic Mechanism of the ω Variation in Moments of Inertia for the Yrast Superdeformed Bands ^194T1（1a,1b）

The variation in moments of inertia(J^(1)and J^(2) with rotational frequency for the superdeformed bands in odd-odd nuclei,194T1(1a,1b),is investigated by using the particle-number conserving method for treating the pairing interaction(monopole and quadrupole),The observed variations ofJ^(1) and J^(2) with ω are reproduced quite well in the calculation and the contributions from each major shell are clearly displayed.     

Theoretical Investigation of the Exotic Structure of the Mirror Nuclei ^17Ne and ^17N

The exotic structures of the ground state of the mirror nuclei ^17Ne and ^17N are investigated by means of the asymptotic normalization coefficient （ANC） method to explore the role of the Coulomb interaction, The probebilities of a valence nucleon outside the binding-potential are P = 56.69±2.98/7.46% for ^17Ne and P = 45.51±2.32/5.81% for ^17N. The rms radii are （r^2）^1/2 = 5.06±0.11/0.30 fm and （r^2）^1/2=4.24±0.06/0.16 fm, respectively. The results obtained are nearly independent of the potential parameters. According to the halo occurrence conditions, it is suggested that ^17Ne is a two-proton halo and ^17N is a two-neutron skin. Moreover, two effects of the Coulomb interact-ion on the exotic structure are analysed. From the present results, the exotic structure of the nucleus in the proton-rich side is more obvious than that of its mirror nucleus because of the Coulomb interaction.     

Systematic Study on the Superdeformed Bands of Double Odd Nuclei in A～130 Region

Properties of the superdeformed bands of odd-odd nuclei in A～130 mass region are investigated systematically within the supersymmetry scheme including many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry on the rotational symmetry. The obtained γ-ray energies, the dynamical moments of inertia, and energy differences △Eγ - △Eγ^ref agree wlth experimental data. It shows that this approach is quite powerful in describing odd-odd nuclei in 130 mass region.     

Influence of Traxiality on the Signature Inversion in Odd-Odd Nuclei

The nature of signature inversion in the πg/2vh11/2 bands of odd-odd^98.102Rh nuclei is studied. Calculations are performed by using a triaxial rotor plus two-quasiparticle model and are compared with the experimentally observed signature inversions. The calculations reproduce well the observations and suggest that, in these bands, the signature inversion can be interpreted mainly as a competition between the Coriolis and the proton-neutron residual interactions in low K space. The triaxiality applied in the Hamiltonian enlarges the amplitudes of high spin signature zigzags at small triaxial deformation and might push the signature inversion point to higher spin at large triaxial deformation.     

Partner of η2（1645） in the 11D2 Meson Nonet

In the qq quark model, the states π2（1670） and η2（1645） are assigned as the I1D2 meson nonet. The partner of state η2（1645） needs further confirmation in the experiments. We employ the meson-meson mixing and the Regge trajectory methods to calculate the mass of the partner of state η2 （1645） to be 1879.8 MeV and 1863 ± 24 MeV respectively. We also calculate the strong decay width in the 3po decay model. These predictions can be compared with experiments in the future.