LHCb实验上核物质效应的重味探针研究进展  

Advances in the studies of nuclear matter effects using heavy-flavor particles as probes at LHCb

作　　者：陈缮真 朱相雷[2] Shanzhen Chen;Xianglei Zhu(Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Department of Engineering Physics,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国科学院高能物理研究所,北京100049 [2]清华大学工程物理系,北京100084

出　　处：《科学通报》2025年第1期70-82,共13页Chinese Science Bulletin

基　　金：国家自然科学基金(12061141007)资助。

摘　　要：相对论重离子碰撞实验的首要物理目标是产生极端高温高密的夸克胶子等离子体新物态并研究其性质.重味强子是碰撞中产生的热密核物质性质和强相互作用非微扰特性的重要实验探针.与之相关的多个实验观测量,比如核修正因子和粒子产额比,表现出对热密核物质效应的敏感性.然而,基于它们来定量提取热密核物质性质还需要对碰撞中的冷核物质效应进行定量限定.LHCb实验参与了LHC上重离子碰撞数据获取,在其独特的前向快度区系统地测量了质子-铅核等碰撞中多种粲、底强子和重夸克偶素的核修正因子以及多种重味强子的产额比,对核物质效应和重味夸克强子化机制进行了深入研究.本文将介绍LHCb实验在这些研究中取得的新进展和未来研究方向.One of the key tasks of high-energy physics is to explore the fundamental composition of matter and its interactions.Bound quarks and gluons were discovered in the 20th century;however,free quarks and gluons have never been observed.This phenomenon is known as“quark confinement”which is one of the fundamental problems in modern physics.Quantum chromodynamics(QCD)is the fundamental theory describing the strong interactions between quarks and gluons,and it predicts that at sufficiently high temperatures,quarks and gluons will be deconfined and form a new state of matter known as the quark-gluon plasma(QGP).This hot and dense state of matter may have existed in the early universe or inside dense celestial bodies.The only way to produce and study the QGP state in the laboratory is through relativistic heavy-ion collisions.Heavy quarks(charm and bottom quarks)have larger masses and can only be produced in the early stages of collision through hard parton scattering processes.They then undergo the entire evolution of the hot and dense QGP state,experiencing frequent scattering with light partons(light quarks or gluons),and eventually become heavy-flavor hadrons either by escaping the medium or by hadronizing along with the QGP medium.The momentum distribution,yield,or cross-section ratios of these heavy-flavor hadrons carry rich information about the QGP state and serve as good experimental probes for the quantitative study of the properties of the hot and dense QGP state.The LHCb experiment,with its unique forward rapidity coverage and excellent capability in measuring heavy-flavor particles,has made numerous significant contributions in the studies of nuclear matter effects with heavy-flavor probes.This article reviews some of the latest results obtained from proton-proton,proton-lead,and lead-lead collision data.Precise measurements of the nuclear modification factors for charm and bottom hadrons in proton-lead collisions have significantly constrained the gluon parton distribution functions at small x,rigorousl

关 键 词：大型强子对撞机 LHCb实验 相对论重离子碰撞 夸克胶子等离子体 核物质效应 重味 

分 类 号：O57[理学—粒子物理与原子核物理]