Physics opportunities at RHIC and LHC

TL;DR

This paper reviews how different nonequilibrium models describe experimental signatures of quark matter formation in heavy ion collisions across SPS, RHIC, and LHC, emphasizing the need for systematic future measurements.

Contribution

It compares various models' predictions with experimental data and highlights the importance of future measurements to understand hot, dense QCD matter.

Findings

Models agree with heavy ion data despite different early phase treatments

Hadron yields and flow observables show consistent patterns across models

Future experiments are crucial for identifying signatures of quark-gluon plasma

Abstract

Nonequilibrium models (three-fluid hydrodynamics, UrQMD, and quark molecular dynamics) are used to discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions from the SPS via RHIC to LHC. It is demonstrated that these models -- although they do treat the most interesting early phase of the collisions quite differently (thermalizing QGP vs. coherent color fields with virtual particles) -- all yield a reasonable agreement with a large variety of the available heavy ion data. Hadron/hyperon yields, including $J/\Psi$ meson production/suppression, strange matter formation, dileptons, and directed flow (bounce-off and squeeze-out) are investigated. Observations of interesting phenomena in dense matter are reported. However, we emphasize the need for systematic future measurements to search for simultaneous irregularities in the excitation functions of several observables in order to come close to pinning the properties of hot, dense QCD matter from data. The role of future experiments with the STAR and ALICE detectors is pointed out.