中高能重离子碰撞中的电磁场效应和手征反常现象  

Electromagnetic field effects and anomalous chiral phenomena in heavy-ion collisions at intermediate and high energy

作　　者：赵新丽 马国亮 马余刚 Zhao Xin-Li;Ma Guo-Liang;Ma Yu-Gang(Key Laboratory of Nuclear Physics and Ion-beam Application,Ministry of Education,Institute of Modern Physics,Fudan University,Shanghai 200433,China;Shanghai Research Center for Theoretical Nuclear Physics,National Natural Science Foundation of China,Fudan University,Shanghai 200438,China)

机构地区：[1]复旦大学现代物理研究所,核物理与离子束应用教育部重点实验室,上海200433 [2]复旦大学,理论物理专款上海核物理理论研究中心,上海200438

出　　处：《物理学报》2023年第11期37-57,共21页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2022YFA1604900);国家自然科学基金(批准号:12147101,11890714,11835002,11961131011,11421505,12105054);中国科学院战略优先研究计划(批准号:XDB34030000);广东省基础与应用基础研究重大项目(批准号:2020B0301030008)资助的课题.

摘　　要：重离子碰撞可以产生极强的电磁场和高温高密量子色动力学(QCD)物质,诱导很多重要手征反常现象,例如手征磁效应和手征磁波.本文围绕手征反常现象中的诸多物理要素,详细介绍包括相对论重离子碰撞中不同碰撞系统和能量下的电磁场特性、同质异位素碰撞中寻找手征磁效应、手征磁波特性、中低能重离子碰撞中磁场效应等一系列与电磁场和手征反常现象相关的理论研究成果.相关研究有助于实验中寻找强相互作用中的电荷宇称(CP)破缺的证据,加深对QCD真空涨落和宇宙中正反物质不对称问题的理解.CP Heavy-ion collisions can produce high-temperature and high-density quantum chromodynamics(QCD)matter under extremely strong electromagnetic fields,which triggers off many important anomalous chiral phenomena,such as the chiral magnetic effect and chiral magnetic wave.The anomalous chiral phenomena can help to find the evidence of symmetry breaking in the strong interaction,deepen the understanding of the QCD vacuum fluctuations,and disclose the mystery of asymmetry of antimatter-matter in the universe.pT<25 pT>25 In this paper,firstly,the magnetic fields are investigated for small and large colliding systems at relativistic heavy ion collider(RHIC)and large hadron collider(LHC).These studies indicate that collision energy and initial nucleon structure have significant effects on magnetic fields.And,the lifetimes of magnetic field in different media are very different in heavy-ion collisions.Then,in order to study the chiral magnetic effect,some experimental observables are studied by using a multi-phase transport model without or with different strengths of the chiral magnetic effect.For small systems,if QGP exists,the chiral magnetic effect could be observed in the peripheral collisions.For isobaric collisions,the correlators with respect to the spectator plane can imply a much cleaner signal of chiral magnetic effect than that with respect to the participant plane.Our results support that the strength of chiral magnetic effect may be absent or small in isobaric collisions.Next,some new strategies are applied to study the chiral magnetic wave.Moreover,a novel mechanism for the electric quadrupole moment can also explain the charge-dependent elliptic flow of pions generated by the chiral magnetic wave.In addition,some interesting phenomena also occur,owing to the magnetic field in heavy-ion collisions at intermediate energy.The directed flow and elliptic flow of photons have no effect on magnetic field at GeV.However,because of the magnetic field,the directed flow of photons decreases and the elliptic flow of

关 键 词：磁场 形变核 手征磁效应 手征磁波 

分 类 号：O571.6[理学—粒子物理与原子核物理]