√SNN=5~12 GeV能区^(197)Au+^(197)Au碰撞中正反质子椭圆流劈裂的研究  

Investigation of the Splitting in Elliptic Flow Between Protons and Anti-protons in (197)Au+^(197)Au Collisions at √SNN=5~12 GeV

作　　者：李鹏程 王永佳[2] 李庆峰[2,3] 张鸿飞[1,4] LI Pengcheng;WANG Yongjia;LI Qingfeng;ZHANG Hongfei(School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;School of Science,Huzhou University,Huzhou 313000,Zhejiang,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;Joint Department for Nuclear Physics,Lanzhou University and Institute of Modern Physics,CAS,Lanzhou 730000,China)

机构地区：[1]兰州大学核科学与技术学院,兰州713000 [2]湖州师范学院理学院,浙江湖州313000 [3]中国科学院近代物理研究所,兰州713000 [4]兰州大学与中国科学院近代物理研究所共建核物理系,兰州713000

出　　处：《原子核物理评论》2020年第3期660-667,共8页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(11875125,11947410,11675066);浙江省自然科学基金资助项目(LY19A050001,LY18A050002)。

摘　　要：利用极端相对论量子分子动力学(Ultra-relativistic Quantum Molecular Dynamics,UrQMD)模型研究了质心系能量√SNN=5~12 GeV能区下^(197)Au+^(197)Au碰撞中正反质子的椭圆流v_(2)及椭圆流v_(2)流差。通过对比含势相互作用与不含势相互作用的两种UrQMD模式下的结果,分析了正反质子椭圆流v_(2)以及椭圆流v_(2)流差随横动量pt、碰撞能量(^(S)NN)1/2、快度y和中心度的变化。发现在考虑平均场势修正后,可以较好地描述质子椭圆流v_(2)、正反质子椭圆流v_(2)流差随横动量pt、碰撞能量√SNN变化的实验数据,并且流差的能量依赖受观测窗口(如:快度和中心度)大小的影响。这些信息对深入理解高密区核物质属性以及探究QCD(Quantum-ChromoDynamical)相图结构有着积极的意义。Utilizing ultra-relativistic quantum molecular dynamics(UrQMD) model,the elliptic flow v_(2) for proton and anti-protons as well as the v_(2) difference between proton and anti-protons from ^(197)Au+^(197)Au collisions at center-of-mass energies √SNN=5 ~ 12 GeV are investigated.By comparing the results from the UrQMD model with and without potential interactions,the v_(2) of protons and anti-protons and their difference as a function of the transverse momentum pt,incident energy√SNN,rapidity and centrality are analyzed.It is found that by including mean-field potentials,the transverse momentum,incident energy dependence of v_(2) of protons and the v_(2) difference in protons and anti-protons could be described well.And the v_(2) difference is affected by the size of the windows(i.e.rapidity and centrality).These information are useful to understand the properties of nuclear matter at high density and thus exploring the structure of QCD(Quantum-ChromoDynamical) phase diagrams.

关 键 词：重离子碰撞 椭圆流 平均场 

分 类 号：O571.53[理学—粒子物理与原子核物理]