高能重离子碰撞中心快度区鉴别粒子的平均横动量  

Midrapidity average transverse momentum of identified charged particles in high-energy heavy-ion collisions

作　　者：谢浈 李景行 郑华[1,2] 张文超[1] 朱励霖 刘星泉[4] 谭志光 周代梅 Bonasera Aldo[7,8] Xie Zhen;Li Jing-Xing;Zheng Hua;Zhang Wen-Chao;Zhu Li-Lin;Liu Xing-Quan;Tan Zhi-Guang;Zhou Dai-Mei;Bonasera Aldo(School of Physics and Information Technology,Shaanxi Normal University,Xi’an 710119,China;Key Laboratory of Quark and Lepton Physics(MOE),Central China Normal University,Wuhan 430079,China;College of Physics,Sichuan University,Chengdu 610064,China;Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China;School of Electronic Information and Electrical Engineering,Changsha University,Changsha 410003,China;Institute of Particle Physics,Central China Normal University,Wuhan 430079,China;Cyclotron Institute,Texas A&M University,College Station,TX 77843,USA;Laboratori Nazionali del Sud,INFN,Catania 95123,Italy)

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710119 [2]华中师范大学夸克与轻子物理教育部重点实验室,武汉430079 [3]四川大学物理学院,成都610064 [4]四川大学原子核科学技术研究所,成都610064 [5]长沙学院电子信息与电气工程学院,长沙410003 [6]华中师范大学粒子物理研究所,武汉430079 [7]德州农工大学回旋加速器实验室,美国得克萨斯州大学城TX 77843 [8]意大利南方国家实验室,意大利卡塔尼亚95123

出　　处：《物理学报》2024年第18期98-111,共14页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11905120);华中师范大学夸克与轻子物理教育部重点实验室开放基金(批准号:QLPL2024P01);四川省自然科学基金面上项目(批准号:2024NSFSC0420)资助的课题。

摘　　要：末态粒子的平均横动量T>是高能重离子碰撞实验中的一个重要观测量.它反映了软质强子的特性和热核物质的性质,对其研究有助于获取碰撞系统的演化信息与规律.基于相对论重离子对撞机(RHIC)上的STAR、PHENIX实验组和大型强子对撞机(LHC)的ALICE实验组提供的金核-金核(Au+Au)和铅核-铅核(Pb+Pb)碰撞中心快度区实验数据,唯象公式能很好地描述不同碰撞能量下,鉴别粒子平均横动量T>随碰撞中心度、每核子对的平均碰撞次数、每核子对平均产生的带电粒子多重数赝快度密度及每次碰撞平均产生的带电粒子多重数赝快度密度的依赖关系.结果表明,鉴别粒子平均横动量T>与碰撞中心度呈线性关系,而与每核子对的平均碰撞次数2N_(coll)/N_(part)、每核子对平均产生的带电粒子多重数赝快度密度2/N_(part)dN_(ch)/dη及每次碰撞平均产生的带电粒子多重数赝快度密度1/N_(coll)dN_(ch)/dη呈幂律关系.同时,发现鉴别粒子平均横动量T>与碰撞中心度以及每核子对的平均碰撞次数唯象公式中的拟合参数与碰撞能量呈现非常好的幂律函数关系.因此,碰撞中心度及每核子对的平均碰撞次数是研究鉴别粒子平均横动量的优选物理量.本文结果可用于对实验上在其他碰撞能量下鉴别粒子平均横动量的预测.The average transverse momentum of final particles is an important observable in high-energy heavyion collision experiments.It reflects the properties of soft hadrons and thermonuclear matter,and it can also be used to deduce the information about the evolution of collision systems.By using the phenomenological linear and power-law functions,we study the dependence of the average transverse momentum at midrapidity in Au+Au and Pb+Pb collisions from the STAR,PHENIX and ALICE Collaborations on four normalized physical quantities,i.e.the collision centrality,the average number of binary collisions per participant pair 2N_(coll)/N_(part),the average pseudorapidity density of charged particles per participant pair 2/N_(part)dN_(ch)/dηand the average pseudorapidity density of charged particles per binary collision 1/N_(coll)dN_(ch)/dη.The results show that the average transverse momentum of identified particles exhibits a good linear relationship with collision centrality,and it follows a nice power-law relationship with the average number of binary collisions per participant pair 2N_(coll)/N_(part),the average pseudorapidity density of charged particles per participant pair 2/N_(part)dN_(ch)/dη,and the average pseudorapidity density of charged particles per binary collision 1/N_(coll)dN_(ch)/dη.It is also found that the fitting parameters in the proposed phenomenological functions for the average transverse momentum with collision centrality and the average number of binary collisions per participant pair follow a power-law function with collision energy,which endows the phenomenological approach with predictive ability.Therefore,the collision centrality and the average number of binary collisions per participant pair are good physical quantities for studying the average transverse momentum of identified particles in high-energy heavy-ion collisions.The results in this study can be used to predict the average transverse momentum of identified particles at other collision energy of which the experimental data are n

关 键 词：重离子碰撞 平均横动量 鉴别粒子 中心快度区 

分 类 号：O571.6[理学—粒子物理与原子核物理]