Collective properties and hard probes of quark-gluon plasma
When the matter is heated up to about two trillion degrees Kelvin,quarks and gluons,that are ordinarily confined inside nucleons and other hadrons,will be deconfined and form a novel state of matter,called quark-gluon plasma.It is believed that shortly after the Big Bang,the early universe was filled with hot and dense quark-gluon plasma.The primary goal of high-energy heavy-ion collisions,such as those performed at the Relativistic Heavy-Ion Collider(RHIC)and the Large Hadron Collider(LHC),is to create quark-gluon plasma in the laboratory,to study its novel properties and to explore the phase structure of strong-interaction matter under extreme conditions of temperatures and densities,etc.Relativistic heavy-ion collisions are many-body dynamical processes that involve the evolutions and interactions of particles and matter at various scales.Due to the color confinement property of quantum chromodynamics and the fundamental quantum field theory of strong interactions,quarks and gluons cannot be directly detected in the laboratory.One of the most important tasks of relativistic heavy-ion collisions is to use the distributions and correlations of the final observed hadrons and other particles,combined with the initial state information of the collisions,to search for various signatures of quark-gluon plasma,to study its macroscopic properties and microscopic structures,and to probe the evolution dynamics of the entire heavy-ion collisions.Jet quenching and collective flow are two smoking-gun signatures for the formation of quark-gluon plasma in relativistic heavy-ion collisions,and they provide very important probes for studying the equation of state,transport properties and evolution dynamics of quark-gluon plasma.A wealth of evidence has shown that the quark-gluon plasma created in heavy-ion collisions at RHIC and the LHC is the hottest,most perfect and extremely opaque fluid ever observed in the laboratory.The dynamical evolution of quark-gluon plasma and the strong collective flows observed in the experiments can be successfully explained by relativistic viscous hydrodynamics,which demonstrates that the quark-gluon plasma is a strongly coupled and nearly perfect liquid,with extremely small shear viscosity to entropy density ratio.Quark-gluon plasma also shows very strong opaqueness to high-energy partonic jets as characterized by significant amount of parton energy loss and strong modification of jet structures,which can trigger supersonic shock waves on the femtometer scale in quark-gluon plasma.In this paper,I will briefly review some recent progress on our understanding of the collective properties and hard probes of quark-gluon plasma in high-energy nuclear collisions,such as initial state fluctuations,anisotropic collective flows,flow fluctuations and correlations,parton energy loss and jet quenching,nuclear modification of full jet and jet structures,jet-induced excitation and medium response,heavy quark dynamics in quark-gluon plasma and hadronization,the production and nuclear modification of heavy flavor hadrons,the collectivity and jet quenching in small systems,etc.
NETL
NSTL
万方数据
维普
