Hydrodynamic aspects of relativistic heavy ion collisions at RHIC

The current status of the application of hydrodynamics to ultrarelativistic heavy ion collisions is reviewed. We elaborate on the arguments for strong transverse flow and rapid thermalization and discuss future applications and trends in hydrodynamics.Comment: Invited plenary talk at SEWM04, Helsinki, June 16-19 200

Hydrodynamic flow at RHIC

We review the apparently hydrodynamic behaviour of low transverse momentum particles (p_T < 1.5 GeV/c) produced in central and semicentral (b < 7 fm) heavy ion collisions at RHIC. We investigate the impact parameter dependence of various observables, elaborating on radial and elliptic flow and particle multiplicities. We also discuss possible ambiguities in the initialization of the hydrodynamic system and present observables that should allow for their resolution.Comment: 10 pages, Proceedings of the 17th Winter Workshop on Nuclear Dynamics, Park City, Utah, 200

Expansion rates at RHIC

A detailed description of the temporal evolution of the thermodynamic fields in heavy ion collisions is presented within a hydrodynamic framework. Particular attention is devoted to the evolution of the collective flow fields and their space-time gradients.Comment: Proceedings for the 19th Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, March 8-15, 2003, 6 page

Emission angle dependent HBT at RHIC and beyond

We study the geometrical features of non-central heavy ion collisions throughout their dynamical evolution from equilibration to thermal freeze-out within a hydrodynamic picture. We discuss resulting observables, in particular the emission angle dependence of the HBT radii and the relation of these oscillations to the geometry at the final stage.Comment: 4 pages, 4 figures, proceedings for Quark Matter 200

Early thermalization at RHIC

It 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.Comment: 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.

Anisotropic flow from AGS to LHC energies

Within hydrodynamics we study the effects of the initial spatial anisotropy in non-central heavy-ion collisions on the momentum distributions of the emitted hadrons. We show that the elliptic flow measured at midrapidity in 158 A GeV/c Pb+Pb collisions can be quantitatively reproduced by hydrodynamic expansion, indicating early thermalization in the collision. We predict the excitation functions of the 2nd and 4th harmonic flow coefficients from AGS to LHC energies and discuss their sensitivity to the quark-hadron phase transition.Comment: 5 pages ReVTeX, incl. 4 figures, subm. to Phys. Lett. B. Improved discussion of results and a few added reference

Momentum anisotropies in the quark coalescence model

Based on the quark coalescence model, we derive relations among the momentum anisotropies of mesons and baryons in relativistic heavy ion collisions from a given, but arbitrary azimuthal distribution for the partons. Besides the familiar even Fourier coefficients such as the elliptic flow, we also pay attention to odd Fourier coefficients such as the directed flow, which has been observed at finite rapidity even at RHIC energies.Comment: 5 page