2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196400A selection of experimental results in high-energy nucleus-nucleus collisions after five years of operation of the Relativistic Heavy-Ion Collider (RHIC) is presented. Emphasis is put on measurements that provide direct information on fundamental properties of high-density QCD matter. The new experimental opportunities accessible at LHC are introduced, in particular those that may help clarify some of the current open issues at RHIC.A few misprints corrected. Matches version to appear in NPANuclear ExperimentHigh Energy Physics - Experimenttext