Heavy-ion collisions at ultra-relativistic energies

Abstract

A brief overview is given on the experimental study of strongly-interacting matter at high energy density as produced in ultra-relativistic heavy-ion collisions, focusing on recent results from the Large Hadron Collider at CERN. Soft particle production is discussed in terms of collective effects, where similarities are observed between nucleus-nucleus collisions and pp and p-Pb collisions, and the multiplicity-dependence of strange hadron yields in all collision systems. Hard probes of the produced Quark-Gluon Plasma (QGP) include jets and hadrons at high transverse momentum, where new measurements in Pb-Pb collisions and, in particular, the analysis of Xe-Xe collisions can provide further details on radiative parton energy loss in the QGP. New results on the production of open heavy-flavor hadrons provide further insight into the transport of heavy charm and beauty quarks in the dense medium and their interactions with it. Finally, measurements on the production of quarkonia give evidence for deconfinement in Pb-Pb collisions at the LHC and could help to determine the initial temperature of the produced QGP.