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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{3. of heavy Ion Accelerator,lanzhou 73.000,China Department of physics Shanghai Jiao Tong University Shanghai 200240 China center of theoretical nuclear{3. National Laboratory of Heavy Ion Accelerator Lanzhou 730000 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

A possible proton pygmy resonance in ^(17)Ne

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 49-52页

作者： MA ZhongYu1,2 & TIAN Yuan1 1 China Institute of Atomic Energy, Beijing 102413. China 2 center of theoretical nuclear physics, national laboratory of heavy collision, lanzhou 73.000, China 1. China Institute of Atomic Energy Beijing 102413 China2. Center of Theoretical Nuclear Physics National Laboratory of Heavy Collision Lanzhou 730000 China

The low-lying electric dipole strengths in proton-rich nuclei 17F and 17Ne, which can be produced at HIRFL-CSR in lanzhou, are investigated. In the framework of the covariant density functional theory the self-consistent relativistic Hartree Bogoliubov model and the relativistic quasiparticle random phase approximation with the NL3.parameter set and Gogny pairing interaction are adopted in the calculations. A pronounced dipole peak appears below 10 MeV in17Ne, but does not occur in 17F. The prop erties of this low-lying E1 excitation in 17Ne are studied, which may correspond to a proton pygmy resonance with different characteristics from those of giant dipole resonance.

关键词： proton pygmy resonance relativistic Hartree-Bogoliubov model relativistic quasiparticle random phase approximation

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{3. physics, national laboratory of heavy Ion Accelerator, lanzhou 73.000, China 1. Department of physics Shanghai Jiao Tong University Shanghai 200240 China 2. center of theoretical nuclear{3. National Laboratory of Heavy Ion Accelerator Lanzhou 730000 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 = (-3.5±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 ± 3.5) MeV, Isym = (-13.9 ± 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

Shape phase transitions in nuclei:Effective order parameters and trajectories

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 88-97页

作者： ZHANG Yu1,2, HOU ZhanFeng2 & LIU YuXin2,3.1Department of physics, Liaoning Normal University, Dalian 116029, China 2Department of physics and the State Key laboratory of{3. physics and Technology, Peking University, Beijing 100871, China 3.5} of theoretical{3. physics, national laboratory of heavy Ion Accelerator, lanzhou 720000, China 1. Department of physics Liaoning Normal University Dalian 116029 China2. Department of Physics and the State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 720000 China

We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.

关键词： nuclear shape phase transition interacting boson model effective order parameter finite particle number effect transition trajectory

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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Science China(physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2,3.1. China Institute of Atomic Energy, Beijing 102413. China 2. center of nuclear theoretical{3., national laboratory of heavy Ion Accelerator of lanzhou, Lan-zhou 73.000, China 3. Institute of theoretical{3., Chinese Academy of Sciences, Beijing 100080, China Correspondence should be addressed to Rong Jian (email: jrong@***) 1. China Institute of Atomic Energy 102413 Beijing China 2. center of nuclear theoretical{3. National Laboratory of Heavy Ion Accelerator of Lanzhou 730000 Lanzhou China 3. Institute of theoretical physics Chinese Academy of Sciences 100080 Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.

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{3. of heavy Ion collisions,lanzhou 73.000,China School of physics Peking University Beijing 100871 China center of theoretical nuclear{3. National Laboratory of Heavy Ion Collisions Lanzhou 730000 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

Criterion for reducible hydrodynamic equations of baryon-rich quark-gluon plasma

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nuclear Science and Techniques 2000年第1期11卷 41-44页

作者： AI Xiao-Bai (Hsiao-bat AI) (center of theoretical nuclear{3., national laboratory of heavy Ion Accelerator, lanzhou 73.000 Shanghai Institule of nuclear Research, the Chinese Academy of Sciences, Shanghai 201800) 兰州原子核理论研究中心重离子加速器国家实验室甘肃兰州 730000

Besides the state equation there exists another cubic algebraic equation about μf in the form of μf3.+ pμf + q = 0, which relates parameters, temperature T, chemical potential μf, and net quark number nff （flavor f） for a baryon-rich quark-gluon plasma （QGP）. A criterion may be acquired simply according to Cardan formula of the solution of the above equation, which gives naturally a condition: if n 2πT3.3. one may approximately use the conservation of specific entropy, and then the set of hydrodynamic equation of baryon-rich QGP may be reduced to the set of hydrodynamic equation for baryon-free QGP.

关键词：重子夸克胶子粒子物理学简化流体动力学方程等离子体 QGP

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,{3. laboratory of heavy Ion Accelerator of lanzhou,lanzhou 73.000,China 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

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

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,{3., China 3.center of theoretical nuclear physics, national laboratory of heavy Ion collisions, Chinese Academy of Sciences,{3., China 4 China center of Advanced Science and Technology (World laboratory), Beijing 100080, China 1. Institute of theoretical physics College of Applied Sciences Beijing University of Technology Beijing 100022 China 3. center of theoretical nuclear{3. 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 2. Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 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