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The study of energy bands in nucleus ^(102)Zr

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Science china(physics,Mechanics & Astronomy) 2010年第1期53卷 106-110页

作者： DONG GuoXiang 1,2 , YU ShaoYing 1,2,3 , LIU YanXin 1 , SHEN CaiWan 1,2,4 & DONG YongSheng 1,2,5I School of Science, Huzhou Teachers College, Huzhou 313000, china 2 School of Science and Information Engineering, Zhejiang Normal University, Jinhua 321000, china 3 Institute of theoretical physics, Chinese Academy of Sciences, Beijing 100080, china 4 center of theoretical nuclear physics, national laboratory of heavy ion accelerator of lanzhou, lanzhou 730000, china 5 Department of physics, Jining Teachers College, Jining 012000, china School of Science Huzhou Teachers College Huzhou China School of Science and Information Engineering Zhejiang Normal University Jinhua China Institute of theoretical physics Chinese Academy of Sciences Beijing China center of theoretical nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China Department of physics Jining Teachers College Jining China

theoretical calculations of the energy bands in nucleus 102 Zr are carried out by taking the projected shell model approach, which has reproduced the experimental data. In addition, by analyzing band-head energies, corresponding configurations of yrast band, quasi-particle rotational bands and side bands, we have worked out the microscopic formation mechanism of axially symmetric deformation bands: The low-excitation deformation bands are attributed to the high-j intruder states 1g 7/2 and 1h 11/2 in the N=4, 5 shells; the quasi-particles in the orbit v5/2-[532], v3/2+[411] and v3/2+[413] in particular play an important role in the deformation of 102 Zr.

关键词： projected shell model yrast band quasi-particle rotational band side band

A phenomenological equation of state for isospin asymmetric nuclear matter

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Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1494-1505页

作者： CHEN LieWen1,2 1 Department of physics,Shanghai Jiao Tong University,Shanghai 200240,china 2 center of theoretical nuclear physics,national laboratory of heavy ion accelerator,lanzhou 730000,china Department of physics Shanghai Jiao Tong University Shanghai China center of theoretical nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China

A phenomenological momentum-independent(MID) model is constructed to describe the equation of state(EOS) for isospin asymmetric nuclear matter,especially the density dependence of the nuclear symmetry energy Esym(ρ).This model can reasonably describe the general properties of the EOS for symmetric nuclear matter and the symmetry energy predicted by both the sophisticated isospin and momentum dependent MDI model and the Skyrme-Hartree-Fock *** find that there exists a nicely linear correlation between Ksym and L as well as between J0/K0 and K0,where L and Ksym represent,respectively,the slope and curvature parameters of the symmetry energy at the normal nuclear density ρ0,while K0 and J0 are,respectively,the incompressibility and the third-order derivative parameter of symmetric nuclear matter at ρ*** correlations together with the empirical constraints on K0,L and Esym(ρ0) lead to an estimation of -477 MeV Ksat,2 -241 MeV for the second-order isospin asymmetry expansion coefficient for the incompressibility of asymmetric nuclear matter at the saturation point.

关键词： equation of state of nuclear matter isospin the symmetry energy

Profile of the composition fractions in neutron stars

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Chinese Science Bulletin 2002年第8期47卷 632-634页

作者： LI Wenfei, ZHANG Fengshou & CHEN Liewencenter of theoretical nuclear physics, national laboratory of heavy ion accelerator, lanzhou 730000, china Institute of Modern physics, Chinese Academy of Sciences, lanzhou 730000, china Department of physics, Shangh center of theoretical nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China Institute of Modern physics Chinese Academy of Sciences Lanzhou China Department of physics Shanghai Jiao Tong University Shanghai China

The composition fractions of β-stable neutron stars and their radial distributions are investigated based on Skyrme-Hartree-Fock theory and Tolman-Oppenheimer-Volkoff (TOV) equation. It is found that a pure neutron interior with a radius of 3.5 km can exist in the neutron stars. When the radius is greater than 3.5 km, the fractions of the proton, electron and μ- appear and increase with the increment of the radius, then decrease after reaching their maximum at the radius of 8 km. These results make it possible to further study the thermal evolution and magnetic properties of the neutron stars.

关键词： neutron stars compositon fractions asymmetric nuclear matter equation of state Tolman-Oppenheimer-Volkoff equation.

Collision dynamics of He@C_(60)+He@C_(60) at low energies

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Science china(physics,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1,2, ZHANG FengShou1,2,3 & ZHOU HongYu1,2 1 Key laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy nuclear physics, Beijing Normal University, Beijing 100875, china 2 Beijing Radiation center, Beijing 100875, china 3 center of theoretical nuclear physics, national laboratory of heavy ion accelerator of lanzhou, lanzhou 730000, china Key laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China Beijing Radiation center Beijing China center of theoretical nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

Higher order bulk characteristic parameters of asymmetric nuclear matter

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 124-129页

作者： CHEN LieWen1,2 1Department of physics, Shanghai Jiao Tong University, Shanghai 200240, china 2center of theoretical nuclear physics, national laboratory of heavy ion accelerator, lanzhou 730000, china Department of physics Shanghai Jiao Tong University Shanghai China center of theoretical nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density ρ0 provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy E0(ρ0) and incompress ibility K0 of symmetric nuclear matter as well as the symmetry energy Esym(ρ0) and its slope parameter L, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain J0 = (-355±95) MeV and I0 = (1473±680) MeV for the third order and fourth-order derivative parameters of symmetric nuclear matter at ρ0 and Ksym = (-100 ± 165) MeV, Jsym = (224 ± 385) MeV, Isym = (-1309 ± 2025) MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at ρ0, using the empirical constraints on E0(ρ0), K0, Esym(ρ0), L, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters E0(ρ0), K0, and J0 can reasonably characterize the EOS of symmetric nuclear matter up to 2ρ0 while the symmetry energy up to 2ρ0 can be well described by Esym(ρ0), L, and Ksym.

关键词： equations of state of nuclear matter forces in hadronic systems and effective interactions symmetry energy nuclear density functional theory and extensions asymmetric matter neutron matter

The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52)Fe

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Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2 & LONG GuiLu1,2 1 Department of physics,Tsinghua University,Beijing 100084,china 2 center of nuclear Theory,national laboratory of heavy ion accelerator of lanzhou,lanzhou 730000,china Department of physics Tsinghua University Beijing China center of nuclear Theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52Fe neutron-proton interaction

Simple Formula of β^+-Decay Half-Lives of Nuclei Far From β-Stable Line

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Communications in theoretical physics 2007年第12期48卷 1072-1080页

作者： ZHANG Xiao-Ping~1 REN Zhong-Zhou~(1,2)and ZHI Qi-Jun~1~1 Department of physics,Nanjing University,Nanjing 210008,china~2 center of theoretical nuclear physics,national laboratory of heavy-ion accelerator,lanzhou 730000,china Department of physics Nanjing University Nanjing 210008 China center of theoretical nuclear physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

We generalize the formula of β^+-decay half-lives [***.C 78 (2006) 014305] to include all availabledata of nuclei far from the β-stable line. Good agreement with experimental data is obtained by taking into accountthe even-odd (e-o) *** is shown that the e-o effect on β^+-deeay half-life is apparent for the allowed β^+-transition,whereas it is not apparent for the first and second forbidden *** demonstrates that the allowed β^+-transitionis more sensitive to the nuclear even-odd effect than the forbidden β^+-*** underlying physics is *** formula can be used to predict the β^+-decay half-lives of the nuclei far from β-*** is useful to experimentalphysicists for analyzing the data of β^+-decay.

关键词： β^+-decay half-lives formula even-odd effect

The low-lying rotational bands of the neutron-rich nucleus ^(172)Tm

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Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1542-1547页

作者： CHEN BaoRen1,LI Tao1 & LIU ShuXin1,2 1 School of physics,Peking University,Beijing 100871,china 2 center of theoretical nuclear physics,national laboratory of heavy ion Collisions,lanzhou 730000,china School of physics Peking University Beijing China center of theoretical nuclear physics National Laboratory of Heavy Ion Collisions Lanzhou China

The microscopic mechanism of four experimentally observed bands in 172Tm is investigated using the particle-number conserving method of the cranked shell model with monopole and quadrupole paring *** experimental results,including the moments of inertia and angular momentum alignments of four bands in 172Tm are reproduced well by the particle-number conserving *** ω variation of the occupation probability of each cranked orbital and the contribution to moment of inertia from each cranked orbital are *** unobserved low-lying bands of 2-quansiparticles in 172Tm are predicted.

关键词： neutron-rich nucleus rare earth rotational band

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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Science china(physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： HUANG YongChang1,3,4, JIANG YunGuo1 & LI XinGuo2,3 1 Institute of theoretical physics, College of Applied Sciences, Beijing University of Technology, Beijing 100022, china 2 Institute of Modern physics, Chinese Academy of Sciences, lanzhou 730000, china 3 center of theoretical nuclear physics, national laboratory of heavy ion Collisions, Chinese Academy of Sciences, lanzhou 730000, china 4 china center of Advanced Science and Technology (World laboratory), Beijing 100080, china Institute of theoretical physics College of Applied Sciences Beijing University of Technology Beijing China center of theoretical nuclear physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou China china center of Advanced Science and Technology (World laboratory) Beijing China Institute of Modern physics Chinese Academy of Sciences Lanzhou China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity