Constraints on symmetry energy and n/p effective mass splitting with improved quantum molecular dynamics model  

作　　者：ZHANG Yingxun LI Zhuxia ZHAO Kai LIU Hang TSANG M B 

机构地区：[1]China Institute of Atomic Energy [2]National Superconducting Cyclotron Laboratory,Michigan State University [3]Texas Advanced Computing Center,University of Texas,Austin

出　　处：《Nuclear Science and Techniques》2013年第5期13-18,共6页核技术（英文）

基　　金：Supported by National Natural Science Foundation of China(NSFC) projects (Nos.11075215,10875031,11005022,11005155 and 11275052);973 Program of China(No.2013CB834404);National Science Foundation(Grants No.PHY-0606007)

摘　　要：A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed.Based on the new code,four commonly used parameter sets,SLy4,SkI2,SkM*and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables,namely isospin transport ratios,single and double ratios of the yields of neutrons and protons are investigated.The isospin transport ratios are strongly sensitive to the slope of symmetry energy,and are not very sensitive to the nucleon effective mass splitting.On the other hand,the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting.By comparing our calculations with the data,we find that the constrained L value(the slope of density dependence of symmetry energy) is about ~46 MeV when the Skyrme type interaction is considered in transport models,and the isospin diffusion data prefer to mn*>mp*,but it is not a strong constraint with deep χ2minimum.A new version of improved quantum molecular dynamics model that includes standard Skyrme interactions has been developed. Based on the new code, four commonly used parameter sets, SLy4, Ski2, SkM＊ and Gs are adopted in the improved quantum molecular dynamics model and the isospin sensitive observables, namely isospin transport ratios, single and double ratios of the yields of neutrons and protons are investigated. The isospin transport ratios are strongly sensitive to the slope of symmetry energy, and are not very sensitive to the nucleon effective mass splitting. On the other hand, the high energy neutrons and protons yields ratios from reactions at different incident energies provide a good observable to the momentum dependence of nucleon effective mass splitting. By comparing our calculations with the data, we find that the constrained L value （the slope of density dependence of symmetry energy） is about -46 MeV when the Skyrme type interaction is considered in transport models, and the isospin diffusion data prefer to mn 〉 mp, but it is not a strong constraint with deep Z2 minimum.

关 键 词：量子分子动力学模型 核子有效质量 对称能 Skyrme相互作用 分裂 密度依赖性 入射能量 运输模型 

分 类 号：O561[理学—原子与分子物理]