  Di-jet correlations in nucleus-nucleus collisions are studied within the
Hadron-String-Dynamics (HSD) transport approach taking into account the
reaction of the medium on the jet energy loss nonperturbatively. A comparison
with the STAR and PHENIX data in central Au+Au collisions at the RHIC energy
$\sqrt{s}=200$ GeV is performed differentially, i.e. with respect to
correlations in azimuthal angle $\Delta \phi$ and pseudorapidity $\Delta \eta$.
The HSD results do not show enough suppression for the `away-side' jets in
accordance with earlier perturbative studies. Furthermore, the `Mach-cone'
structure for the angle distribution in the `away-side' jet as well as `ridge'
long rapidity correlations in the `near-side' jet - observed by the STAR and
PHOBOS Collaborations - are not seen in the HSD results, thus suggesting a
partonic origin.
