RHIC能区Au+Au碰撞中带电粒子直接流与超子整体极化的计算与分析  

The direct flow of charged particles and the global polarization of hyperons in 200 AGeV Au+Au collisions at RHIC

作　　者：江泽方 吴祥宇 余华清 曹杉杉 张本威[2] Jiang Ze-Fang;Wu Xiang-Yu;Yu Hua-Qing;Cao Shan-Shan;Zhang Ben-Wei(College of Physics and Electronic Information Engineering,Hubei Engineering University,Xiaogan 432000,China;Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOE),Central China Normal University,Wuhan 430079,China;Institute of Frontier and Interdisciplinary Science,Shandong University,Qingdao 266237,China)

机构地区：[1]湖北工程学院物理与电子信息工程学院,孝感432000 [2]华中师范大学物理学院,粒子物理研究所,夸克与轻子物理教育部重点实验室,武汉430079 [3]山东大学前沿交叉科学青岛研究院,青岛266237

出　　处：《物理学报》2023年第7期163-171,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11935007,12175122,2021-867);广东省基础与应用基础研究重大专项(批准号:2020B0301030008);湖北省自然科学基金(批准号:2021CFB272);湖北省教育厅中青年人才项目(批准号:Q20212703);教育部夸克与轻子物理重点实验室开放基金(批准号:QLPL202104)资助的课题。

摘　　要：非对心的相对论重离子碰撞中,不参与碰撞的核子会对参与碰撞的核子产生纵向拖拽,形成一个相对于纵向倾斜的夸克胶子等离子体(QGP)火球.同时,对撞的原子核可将巨大的轨道角动量沉积于QGP中,使其中的部分子沿系统总角动量方向发生自旋极化.在光学Glauber模型基础上,本文构建了倾斜的三维QGP初态条件,并结合3+1维黏滞流体力学模型CL Visc,研究了重离子碰撞的末态带电粒子的直接流和Λ/Λ超子的整体极化.计算表明,倾斜的初态条件与流体力学模型的结合能够较好地描述RHIC-STAR实验上观测到的直接流与超子整体自旋极化的数据.这为人们利用这些观测量进一步约束重离子碰撞产生的核物质的初始几何与运动学状态提供了理论依据.In non-central relativistic heavy-ion collisions,the non-colliding nucleons drag the colliding nucleons along the longitudinal direction asymmetrically,producing a longitudinally tilted quark-gluon plasma(QGP)fireball.Meanwhile,these colliding nuclei deposit a huge initial orbital angular momentum into the system,leading to the polarization of partons inside the QGP along the direction of the total angular momentum.Based on the optical Glauber model,we develop a 3-dimensional initial condition of the tilted QGP.By combining it with the(3+1)-dimensional viscous hydrodynamic model CLVisc,we investigate the directed flow of charged hadrons and the global polarization ofΛ/Λhyperons in heavy-ion collisions.Our calculation indicates that the combination of a tilted initial condition of the QGP and the hydrodynamic model can provide a satisfactory description of the directed flow and global polarization observed at RHIC-STAR.This offers a theoretical baseline for using these observables to further constrain the initial geometry and kinematic properties of the nuclear matter created in heavy-ion collisions.

关 键 词：相对论重离子碰撞 夸克胶子等离子体 直接流 Λ/Λ超子整体自旋极化 

分 类 号：O571.6[理学—粒子物理与原子核物理]