中能区重离子碰撞中椭圆流的动力学产生机制分析  

Analysis of the dynamical mechanism for elliptic flow production in heavy-ion collisions at intermediate energies

作　　者：崔特 刘玲[1] 李鹏程 王永佳[2] 李庆峰[2,1,3,4] CUI Te;LIU Ling;LI PengCheng;WANG YongJia;LI QingFeng(College of Physics Science and Technology,Shenyang Normal University,Shenyang 110034,China;School of Science,Huzhau University,Huzhou 313000,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;Institute of Modem Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]沈阳师范大学物理科学与技术学院,沈阳110034 [2]湖州师范学院理学院,湖州313000 [3]兰州大学核科学与技术学院,兰州730000 [4]中国科学院近代物理研究所,兰州730000

出　　处：《中国科学：物理学、力学、天文学》2021年第8期48-54,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:11875125,U2032145,12047568);国家重点研发计划(编号:2020YFE0202002);浙江省“万人计划”资助项目。

摘　　要：近年来,椭圆流(v2)作为研究重离子碰撞动力学过程的重要观测量之一而备受关注.本文基于极端相对论量子分子动力学(UrQMD)模型,反向追踪反应末态处于中心快度区(|y0|<0.1)的核子的演化过程,探究这些核子的v2随时间的变化.通过分别记录这些核子在平均场、核子-核子碰撞作用前后的v2来探究这两部分对v2产生的影响.以入射能量为每核子0.4 GeV、碰撞参数为5 fm的Au+Au碰撞为例,计算结果表明平均场对中心快度区核子的v2的贡献大约占30%,而碰撞对它的贡献约占70%.此外,还发现不考虑碰撞项中的泡利阻塞效应时给出的v2比考虑泡利阻塞效应时的要大10%左右.Elliptic flow(v2) is an essential observable for studying the dynamic process of heavy-ion collisions, and has attracted significant attention in recent years. Based on the ultra-relativistic quantum molecular dynamics model, by tracking the nucleons that are emitted at mid-rapidity(|y0| < 0.1) in the entire collision process, the time evolution of elliptic flow of these selected nucleons is studied. The contributions of the mean-field potential and collision term to the elliptic flow are disentangled by recording the momenta of nucleons before and after each collision and propagation in the potential. In the semi-peripheral(b=5 fm) Au+Au collision at Ebeam= 0.4 GeV/nucleon, approximately 30% of the v2 is attributed to the mean-field potential, while the remaining 70% is attributed to the nucleon-nucleon collisions. v2 is further increased(by approximately 10%) if the Pauli blocking effect is excluded.

关 键 词：重离子碰撞 椭圆流 平均场 核子-核子碰撞 

分 类 号：O571.6[理学—粒子物理与原子核物理]