We present an introductory review of the early time dynamics of high-energy heavy-ion collisions and the kinetics of high temperature QCD. The equilibration mechanisms in the quark-gluon plasma uniquely reflect the non-abelian and ultra-relativistic character of the many body system. Starting with a brief expose of the key theoretical and experimental questions, we provide an overview of the theoretical tools employed in weak coupling studies of the early time non-equilibrium dynamics. We highlight theoretical progress in understanding different thermalization mechanisms in weakly coupled non-abelian plasmas, and discuss their relevance in describing the approach to local thermal equilibrium during the first ${\rm fm}/c$ of a heavy-ion collision. Some important connections to the phenomenology of heavy-ion collisions are also briefly discussed.
We review the theoretical aspects relevant in the description of high energy heavy ion collisions, with an emphasis on the learnings about the underlying QCD phenomena that have emerged from these collisions.
Heavy flavor supplies a chance to constrain and improve the hadronization mechanism. We have established a sequential coalescence model with charm conservation and applied it to the charmed hadron production in heavy ion collisions. The charm conservation enhances the earlier hadron production and suppresses the later production. This relative enhancement (suppression) changes significantly the ratios between charmed hadrons in heavy ion collisions.
We perform an analysis of jet quenching in heavy and light ion collisions for scenarios without and with quark-gluon plasma formation in $pp$ collisions. We find that the results for these scenarios are very similar, and both of them are in reasonable agreement with data for heavy ion collisions. However, their results become differ significantly for light nuclei. Using the parameters fitted to heavy ion data on the nuclear modification factor $R_{AA}$, we make predictions for 0.2 and 7 TeV O+O collisions that can be verified by future experiments at RHIC and the LHC.
Heavy flavor hadrons have long been considered as a probe of the quark gluon plasma created in high energy nuclear collisions. In this paper we review the heavy flavor properties under extreme conditions and the realization in heavy ion experiments. After a short introduction on heavy flavor properties in vacuum, we emphasize the cold and hot nuclear matter effects on heavy flavors, including shadowing effect, Cronin effect and nuclear absorption for the former and Debye screening and regeneration for the latter. Then we discuss, in the frame of transport and coalescence models, these medium i…
Heavy ion collisions pose interesting challenges to quantum chromodynamics, because they probe the parton structure of the incoming nuclei at very small longitudinal momentum fractions. Combined with the large size of nuclei, this may lead to the phenomenon of gluon saturation. The Color Glass Condensate is an effective QCD description that aims to cope with such a situation. In this talk, I show how one may study heavy ion collisions in this framework.
Shannon information entropy provides an effective tool to study the evolution process in relativistic heavy-ion collisions. The time evolution process of thermodynamic entropy $S_{\rm thermal}$, multiple entropy $S_{\rm mul}$, and configuration entropy $S_{\rm conf}$ at RHIC is studied using the AMPT model to generate central Au-Au collisions. By superimposing the three kinds of information entropy, we can get a more complete information entropy of the system to describe the physical information of the relativistic heavy ion collision. The results show that the four stages of the time evolutio…
I argue that perturbative scattering of quarks and gluons are incompatible with lattice and heavy ion data on QGP properties. The non-perturbative mechanisms for quasiparticle rescattering and quark production are briefly discussed, as well as experiments needed to measure matter anisotropy and quark density at early stages of the collisions.
In heavy-ion collisions the electromagnetic field exists before the hot nuclear matter emergence. Requiring the field continuity we compute it in the central rapidity region by taking into account the electromagnetic response of the Quark Gluon Plasma. We show that the electromagnetic field is nearly time-independent from about 1~fm/c after the collision until the freezeout.
I give a brief overview of the science cases of the Electron-Ion Collider (EIC) with a particular emphasis on the connections to the physics of ultrarelativistic heavy-ion collisions.
We present a simple way to construct 3D initial conditions for relativistic heavy-ion collisions based on the Glauber collision geometry. Local energy and momentum conservation conditions are imposed to set non-trivial constraints on our parameterizations of longitudinal profiles for the system's initial energy density and flow velocity. After calibrating parameters with charged hadron rapidity distributions in central Au+Au collisions, we test model predictions for particle rapidity distributions in d+Au and peripheral Au+Au collisions in the Beam Energy Scan (BES) program at Relativistic Hea…
We extend our POWLANG transport setup for the modelling of heavy-flavour production in heavy-ion collisions to the case of full 3+1 simulations, dropping the approximation of longitudinal boost-invariance of the background medium. This enables us to provide predictions for observables for which the rapidity dependence is essential in order to obtain a non-vanishing signal, like the directed flow $v_1$, and to get reliable results also for kinematic distributions of heavy-flavour particles at forward rapidity. We compare our predictions with experimental data obtained in Au-Au and Pb-Pb collisi…
