2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/178936It is shown that recent RHIC data on hadron spectra and elliptic flow can be excellently reproduced within a hydrodynamic description of the collision dynamics, and that this provides strong evidence for rapid thermalization while the system is still in the quark-gluon plasma phase. But even though the hydrodynamic approach provides an impressive description of the single-particle momentum distributions, it fails to describe the two-particle momentum correlation (HBT) data for central Au+Au collisions at RHIC. We suggest that this is not likely to be repaired by further improvements in our understanding of the early collision stages, but probably requires a better modelling of the freeze-out process. We close with a prediction of the phases of the azimuthal oscillations of the HBT radii in noncentral collisions at RHIC.12 pages, including 6 figures. Invited talk at the International Conference on "Statistical QCD", Bielefeld, August 26-30, 2001, to appear in the proceedings (F. Karsch and H. Satz, eds.) in Nucl. Phys. AHigh Energy Physics - Phenomenologytext