QM2017: Status and Key open Questions in Ultra-Relativistic Heavy-Ion Physics

Abstract

Almost exactly 3 decades ago, in the fall of 1986, the era of experimental ultra-relativistic (\emph{E/m $\gg 1$}) heavy ion physics started simultaneously at the SPS at CERN and the AGS at Brookhaven with first beams of light Oxygen ions at fixed target energies of 200 GeV/A and 14.6 GeV/A, respectively. The event was announced by CERN \cite{cernpress1,cernpress2} with the usual superlatives "Break new ground.., World Record Energy ..", but also with the information that "up to 400 particles were created per collision" and that "over 300 physicists .. analyzing the data .. [try] to find out whether the famous quark-gluon plasma really has been achieved". One would have thought that with almost one physicist per particle, this would have been figured out rather quickly. However, as we know today, 30 years and 21 Quark Matter conferences later, the study of dense and hot matter, of the strong interaction in the non-perturbative regime, has been a long and winding road. The journey was much more difficult and time consuming, but also much more interesting and rewarding, than anyone could have anticipated, with many twists, some dead ends, and a never-ending string of surprises. This $30^{th}$ anniversary of heavy ion physics, and the start of the 26${}^{th}$ Quark Matter in Chicago, is a good opportunity to look back and mention a few of the major results from each of the three eras (fixed target/RHIC/LHC), along with some of the answers they have provided us and some of the key questions which remain to be solved.

Opening Talk of the 'XXVIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2017)

References in corpus (11)

• Fluid Dynamics far from Local Equilibrium
• Results from the Relativistic Heavy Ion Collider
• Thermal Hadronization and Hawking-Unruh Radiation in QCD
• Hadron yields and the phase diagram of strongly interacting matter
• NA60 results on thermal dimuons
• Observation of a "Ridge" correlation structure in high multiplicity proton-proton collisions: A brief review
• Shape and flow fluctuations in ultra-central Pb+Pb collisions at the LHC
• Effects of Overlapping Strings in pp Collisions
• Highlights from BNL-RHIC 2011-2013
• Effect of initial-state nucleon-nucleon correlations on collective flow in ultra-central heavy-ion collisions
• The Future of High Energy Nuclear Physics in Europe

Cited by in corpus (19)

• Measurement of the azimuthal anisotropy of charged particles produced in $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV Pb+Pb collisions with the ATLAS detector
• Relativistic Hydrodynamic Attractors with Broken Symmetries: Non-Conformal and Non-Homogeneous
• Testing coalescence and statistical-thermal production scenarios for (anti-)(hyper-)nuclei and exotic QCD objects at energies available at the CERN Large Hadron Collider
• Measurement of flow harmonics correlations with mean transverse momentum in lead-lead and proton-lead collisions at $\sqrt{s_{NN}}=5.02$ TeV with the ATLAS detector
• Relativistic Fluid Dynamics In and Out of Equilibrium -- Ten Years of Progress in Theory and Numerical Simulations of Nuclear Collisions
• Holographic Heavy-Ion Collisions: Analytic Solutions with Longitudinal Flow, Elliptic Flow and Vorticity
• Dilepton production and elliptic flow from an anisotropic quark-gluon plasma
• Anisotropic hydrodynamics with a scalar collisional kernel
• (3+1)-dimensional anisotropic fluid dynamics with a lattice QCD equation of state
• Probing the transport properties of Quark-Gluon Plasma via heavy-flavor Boltzmann and Langevin dynamics
• $J/\psi$ regeneration in a hadron gas: an update
• Production of open-charm mesons in relativistic heavy-ion collisions
• Confronting Experimental Data with Heavy-Ion Models: Rivet for Heavy Ions
• Parton self-energies for general momentum-space anisotropy
• Charm-strange meson production in ultra-relativistic heavy-ion collisions at the CERN-LHC energies
• Bottomonium suppression in PbPb collision at energies available at the CERN large hadron collider
• Testing production scenarios for (anti-)(hyper-)nuclei with multiplicity-dependent measurements at the LHC
• Probing the tricritical endpoint of QCD phase diagram at NICA-FAIR energies
• Observation of Universal Expansion Anisotropy from Cold Atoms to Hot Quark-Gluon Plasma