IMF production and symmetry energy in heavy ion collisions near Fermi energy  

作　　者：WADA Roy HUANG Meirong LIN Weiping LIU Xingquan ZHAO Minghui CHEN Zhiqiang 

机构地区：[1]Institute of Modern Physics,Chinese Academy of Science [2]University of Chinese Academy of Sciences

出　　处：《Nuclear Science and Techniques》2013年第5期1-6,共6页核技术（英文）

基　　金：Supported by National Natural Science Foundation of China(NSFC) Projects (No.11075189);"100 Persons Project(Nos.0910020BR0 and Y010110BR0)";"ADS project 302"of the Chinese Academy of Sciences(No.Y103010ADS);supported by U.S.Department of Energy(Grant No.DE-FG03-93ER40773);Robert A.Welch Foundation(Grant A0330)

摘　　要：The symmetry energy at the time of the production of intermediate mass fragments(IMFs) is studied using experimentally observed IMF multiplicities combined with quantum statistical model calculations(QSM of Hahn and St cker).The ratios of difference in chemical potentials between neutrons and protons relative to the temperature,(μn-μp)/T,and the double ratio temperature,T,were extracted experimentally in the reactions of64,70Zn,64Ni+58,64Ni,112,124Sn,197Au,232Th at 40A MeV.The extracted(μn-μp)/TTscales linearly with δNN,where δNN is the asymmetry parameter,(N-Z)/A,of the emitting source and(μn-μp)/T=(11.1 1.4)δNN0.21 was derived.The experimentally extracted(μn-μp)/T and the double ratio temperatures are compared with those from the QSM calculations.The temperatures-,T,and densities,ρ,extracted from the(μn-μp)/T values agreed with those from the double ratio thermometer which used the yield ratios of d,t,h and α particles.However the two analyses of the differential chemical potential analysis and the initial temperature analysis end up almost identical relation between T and ρ.T=5.25±0.75 MeV is evaluated from the(μn-μp)/Tanalysis,but no density determination was possible.From the extracted T value,the symmetry energy coefficient Esym =14.6±3.5 MeV is determined for the emitting source of T=5.25±0.75 MeV.The symmetry energy at the time of the production of intermediate mass fragments （IMFs） is studied using experimentally observed IMF multiplicities combined with quantum statistical model calculations （QSM of Hahn and Stfcker）. The ratios of difference in chemical potentials between neutrons and protons relative to the temperature,（μt- μp） /T, and the double ratio temperature, T, were extracted experimentally in the reactions of 64＇7~Zn, 64Ni＋58＇64Ni, 112＇124Sn, 197Au, 232Th at 40A MeV. The extracted （μt- μp） / T scales linearly with Jwv, where fi^v is the asymmetry parameter, （N-Z）/A, of the emitting source and （μt- μp） / T = （11.1 ＋ 1.4）rNN -- 0.21 was derived. The experimentally extracted （μt-μp）/T and the double ratio temperatures are compared with those from the QSM calculations. The temperatures, T, and densities, p, extracted from the （μn - μp） / T values agreed with those from the double ratio thermometer which used the yield ratios of d, t, h and a particles. However the two analyses of the differential chemical potential analysis and the initial temperature analysis end up almost identical relation between T and p. T=5.25±0.75 MeV is evaluated from the （μn -μp） / T analysis, but no density determination was possible. From the extracted T value, the symmetry energy coefficient Esym=14.6±3.5 MeV is determined for the emitting source of T=5.25±0.75 MeV.

关 键 词：国际货币基金组织 对称能 重离子碰撞 生产 费米能 量子统计模型 实验观察 中等质量碎片 

分 类 号：O571.6[理学—粒子物理与原子核物理]