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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 2.02.0,China 2.center of {2. nuclear physics,national laboratory of heavy ion accelerator,lanzhou 730000,China Department of physics Shanghai Jiao Tong University Shanghai 200240 China center of theoretical {2. physics 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.-2.1 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

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 2.02.0, China 2.1} of {2. nuclear physics, national laboratory of heavy ion accelerator, lanzhou 730000, China 1. Department of physics Shanghai Jiao Tong University Shanghai 200240 China 2. center of theoretical {2. physics 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 informat{2. on the equat{2. 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 correlat{2.s between the lower and higher order bulk char acteristic parameters within the framework of Skyrme Hartree-Fock energy density funct{2.al 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 = (2.4 ± 385) MeV, Isym = (-1309 ± 2.2.) 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 2.0 while the symmetry energy up to 2.0 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 11602., China 2.epartment of physics and the State Key {2. of nuclear physics and Technology, Peking University, Beijing 100871, China 3center of theoretical nuclear physics, national laboratory of heavy ion accelerator, lanzhou 72.000, 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. 2. → 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

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 {2. physics, national laboratory of heavy ion accelerator, lanzhou 730000 Shanghai Institule of {2. Research, the Chinese Academy of Sciences, Shanghai 2.1800) 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 2.T3/3, 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 {2. Theory,national laboratory of heavy ion accelerator of lanzhou,lanzhou 730000,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 52.e neutron-proton interaction

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 102.13, China 2. center of nuclear {2. physics, national laboratory of heavy ion accelerator of lanzhou, Lan-zhou 730000, China 3. Institute of {2. physics, 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 {2. physics 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.

Half-lives and fine structure for the α decay of deformed even-even nuclei

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 24-31页

作者： NI DongDong1,2.& REN ZhongZhou1,2.3 1Department of physics, Nanjing University, Nanjing 2.0093, China 2.avli Institute for theoretical physics China, Beijing 100190, China 3center of theoretical nuclear physics, national laboratory of heavy-ion accelerator, lanzhou 730000, China Nanjing Univ Dept Phys Nanjing 210093 Jiangsu Peoples R China Kavli Inst Theoret Phys China Beijing 100190 Peoples R China Ctr Theoret Nucl Phys Natl Lab Heavy Ion Accelerator Lanzhou 730000 Peoples R China

The α-decay properties of well-deformed even-even nuclei are systematically calculated within the multichannel cluster model (MCCM). Instead of working in the WKB framework, the quasibound solution to the coupled Schro¨dinger equation is presented with outgoing wave boundary conditions, and the coupling potential is taken into full account in terms of the general quantum theories. The calculated α-decay half-lives are found to agree well with the experimental data with a mean factor of less than 2. The fine structure observed in α decay is also well reproduced by the four-channel microscopic calculation. Very strikingly, the MCCM can give relatively precise descriptions of the branching ratio to excited 4+ states, which is often overestimated in the usual WKB calculations. We expect it to be a significant development of theoretical models toward quantitative descriptions of α transitions to high-spin daughter states.

关键词： α decay half-lives cluster model coupled channel approach

Systematic study of survival probability of excited superheavy nuclei

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 109-113页

作者： XIA ChengJun1, SUN BaoXi1, ZHAO EnGuang2.3 & ZHOU ShanGui2.3 1College of Applied Sciences, Beijing University of Technology, Beijing 10012., China 2.nstitute of theoretical physics, Chinese Academy of Sciences, Beijing 100190, China {2., national laboratory of heavy ion accelerator, lanzhou 730000, China Chinese Acad Sci Inst Theoret Phys Beijing 100190 Peoples R China Beijing Univ Technol Coll Appl Sci Beijing 100124 Peoples R China Ctr Theoret Nucl Phys Natl Lab Heavy Ion Accelerator Lanzhou 730000 Peoples R China

The stability of excited superheavy nuclei (SHN) with 100 Z 134 against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. The present calculations consistently take the neutron separation energies and shell correction energies from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z = 115 and N = 179. It turns out that this island of stability persists for excited SHN in the sense that the calculated survival probabilities in the 1n-channel of excited SHN at the optimal excitation energy are maximized around Z = 115 and N = 179. This indicates that the survival probability in the 1n-channel is mainly determined by the nuclear shell effects.

关键词： survival probability superheavy elements island of stability neutron emission fission

Analysis of the negative-parity yrast band in ^(155)Tb

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nuclear Science and Techniques 2000年第1期11卷 55-59页

作者： WU Xing-Ju XU Jin-Zhang CHEN Xing-Qu (center of theoretical {2. physics, national laboratory of heavy ion accelerator, lanzhou 730000 physics Department,Lu-an Teacher’s College,Lu-an, Anhui 2.7012.Department of Modern physics, lanzhou University, 六安师范专科学校重离子加速器国家实验室安徽六安 237012 兰州大学现代物理系重离子加速器国家实验室甘肃兰州 730000

Using the particle-rotor model, the energy spectrum and the B（MI）/B（E2. ratio of the negative-parity yrast band in 155Tb are investigated and compared with the experimental data before and after the band-crossing. It is noted that before and after the band-crossing the moment of inertia of the core is a smooth function of the total angular momentum I and can be described by the ah formula. The yrast band of 155Tb with negative parity may be triaxially deformed （γ=-13°） before and an axially symmetric shape （γ=0°） after the band-crossing.

关键词：铽155 原子核高自旋态结构性质负跃迁晕转态核子