- th / 0 70 20 79 v 1 2 6 Fe b 20 07 Hard and soft probe - medium interactions in a 3 D hydro + micro approach at RHIC

We utilize a 3D hybrid hydro+micro model for a comprehensive and consistent description of soft and hard particle production in ultra-relativistic heavy-ion collisions at RHIC. In the soft sector we focus on the dynamics of (multi-)strange baryons, where a clear strangeness dependence of their collision rates and freeze-out is observed. In the hard sector we study the radiative energy loss of hard partons in a soft medium in the multiple soft scattering approximation. While the nuclear suppression factor R AA does not reflect the high quality of the medium description (except in a reduced systematic uncertainty in extracting the quenching power of the medium), the hydrodynamical model also allows to study different centralities and in particular the angular variation of R AA with respect to the reaction plane, allowing for a controlled variation of the in-medium path-length. Experiments at the Relativistic Heavy Ion Collider (RHIC) have established a significant suppression of high-p T hadrons produced in central A+A collisions compared to those produced in peripheral A+A or binary scaled p+p reactions, indicating a strong nuclear medium effect [1, 2], commonly referred to as jet-quenching. Within the framework of perturbative QCD, the leading process of energy loss of a fast parton is gluon radiation induced by multiple soft collisions of the leading parton or the radiated gluon with color charges in the quasi-thermal medium [3, 4, 5]. Over the past two years, a large amount of jet-quenching related experimental data has become available including but not limited to the nuclear modification factor R AA , the elliptic flow v 2 at high p T (as a measure of the azimuthal anisotropy of the jet cross section) and a whole array of high p T hadron-hadron correlations. Computations of such jet modifications have acquired a certain level of sophistication regarding the incorporation of the partonic processes involved. However, most of these calculations