中能重离子碰撞中集体流的同位旋效应  

Isospin Effects on Collective Flow in HIC at Intermediate Energies

作　　者：陈列文[1] 张丰收[1] 曾祥华[1] 靳根明[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《高能物理与核物理》1998年第11期1035-1041,共7页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金!19609033;中国科学院基金;国家教委留学人员科研费资助

摘　　要：在同位旋相关的量子分子动力学模型的基础上，利用Skyrme－Hartree－Fock计算所得的中子、质子密度，同时利用费米气体模型得到相应的中子、质子费米面，抽样出稳定的(58)Fe和(58)Ni初始核．仔细研究了(55)MeV／u(58)Fe＋(58)Fe和55MeV／u(58)Ni＋(58)Ni两个反应中集体流的同位旋效应．在不同碰撞参数下对不同类型的碎块，观察到丰中子反应系统(58)Fe＋(58)Fe比(58)Ni＋(58)Ni有更强的集体流，并能与实验结果定性符合．同时，研究了同位旋相关的对称能与核子－核子碰撞截面对集体流的影响。Based on an isospin-dependent quantum molecular dynanics model, the neutron and proton density calculated from Skyrme-Hartree-Fock theory, along with the neutron and proton Fermi momenta calculated from Fermi gas model, are used to sample stable initial nuclei, 58Fe and 58Ni. The isospin effects on collective flow in reaction systems 55MeV/u 58Fe + 58Fe and 55MeV/u 58Ni+58Ni are studied in detail.At different impact parameters for different types of fragments, it is shown that the neutron-rich system 58Fe + 58Fe has stronger collective flow than the system 58Ni+58Ni,which could qualitatively agree with the results of the experiments. Meanwhile, the effects of both isospin-dependent symmetry energy and nucleon-nucleon cross sections on collective flow are studied.

关 键 词：QMD模型 集体流 同位旋效应 重离子碰撞 

分 类 号：O571.426[理学—粒子物理与原子核物理]