相对论重离子碰撞中的喷注淬火和介质响应

Jet quenching and medium response in relativistic heavy-ion collisions

本文简要回顾近年来在相对论重离子碰撞中喷注与夸克胶子等离子体相互作用方面的一些研究工作和进展,主要讨论以下4个方面:领头强子、整体喷注、重味夸克和介质响应.大横动量领头强子谱的压低是喷注淬火研究中最早被关注的观测量之一.在大横动量区间,系统研究了喷注淬火对部分子味道的依赖性,细致考虑了高能夸克和胶子对轻强子和重味强子的产生和核压低的贡献.在中低横动量区间,发现夸克组合机制和非微扰相互作用对解释轻强子和重味强子的核修正因子与椭圆流数据至关重要.整体喷注是近年来喷注淬火研究中的一个热点.利用贝叶斯分析研究了单举喷注和光子-喷注的横动量谱压低效应,定量提取了整体喷注的能量损失及其分布.系统性地研究了整体喷注的内部结构,如喷注形状函数、喷注腰围和喷注横动量弥散、整饰喷注的劈裂函数和劈裂半径、重组大半径喷注以及喷注内重味强子的径向分布等.介质响应一直是喷注淬火研究中的一个重点和难点.喷注在夸克胶子等离子体中的能动量损失会在喷注的传输方向激发出马赫锥等效应,同时在后方会产生扩散尾流.细致研究了介质响应对喷注周围的能量分布以及重子介子产额比的影响;提出了在光子或Z玻色子标记的喷注事例中探测扩散尾流的二维和三维结构的新方法.

We briefly review some recent studies pertaining to jet-medium interaction and jet quenching in high-energy heavy-ion collisions.We focus on the following four topics:leading hadrons,full jets,heavy quarks,and medium response.The suppression of large-transverse-momentum hadrons served as a crucial signature of jet quenching in relativistic heavy-ion collisions.In the large-transverse-momentum regime,we discuss the flavor hierarchy of jet quenching by considering the contributions of both quarks and gluons to heavy and light hadron production,alongside the effect of nuclear modification.In the low and intermediate transverse momentum regimes,we discuss the crucial roles of quark coalescence and nonperturbative interactions to further our understanding of nuclear modification and the elliptic flow of light-and heavy-flavor hadrons.Recently,full jets and their nuclear modification have emerged as prominent topics of research within the field.Herein,we discuss the first Bayesian extraction of jet energy-loss distribution from a single inclusive jet and photon-tagged jet data.Additionally,we present several recent studies on jet structure and substructure observables,including jet shape,jet girth,transverse momentum dispersion,groomed jet-splitting momentum fraction and radius,reclustered large-radius jets,and heavy-meson distribution within jets.Jet-induced medium response has been a hot and difficult topic for a long time.Jet quenching not only triggers a Mach cone and wavefront around the propagating jet but also generates a diffusion wake behind the jet.We present some recent studies regarding medium response effect in jet-related observables.In particular,we discuss how jet-induced medium response affects the energy distribution and hadron chemistry around the quenched jets,and how to detect the two-and three-dimensional structures of diffusion wake in photon/Z-tagged jet events.