Systematic Comparison of Jet Energy-Loss Schemes in a 3D hydrodynamic medium

We perform a systematic comparison of jet energy-loss calculations in the BDMPS/ASW, HT and AMY approaches. Since we use identical medium evolution in all three approaches we are in a unique position to isolate differences among the three calculations solely due to their energy-loss implementation. We find that the parameters of all three calculations can be adjusted to provide a good description of inclusive data on $R_{AA}$ versus transverse momentum. However, we do observe slight differences in their predictions for the centrality- and azimuthal angular dependence of $R_{AA}$ vs. $p_T$. We also note that the value of the transport coefficient $\hat{q}$ needed in the three approaches to describe the data differs significantly. We shall attempt to shed some light onto this {\it $\hat{q}$-puzzle}.