Dijet asymmetry based on an analytic Glauber model and path length dependent energy loss computations in Pb+Pb collisions

Preliminary ATLAS results from Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV show a dependence of the dijet asymmetry on the angle $(\Delta \phi)$ of the leading jet with respect to the event plane on the order of 2-3\% for mid-range centrality collisions. Using an analytic Glauber model to simulate heavy ion interactions, we computed path length dependent energy loss for simulated dijet events in Pb+Pb collisions, with initial energy and parton flavors determined based on PYTHIA calculations of p+p collisions. We observe a $\Delta \phi$ and impact parameter dependent behaviour similar to that observed in the experiment. We also show that this $p_T$-independent energy loss is not sufficient to reproduce the single jet nuclear modification factor $(R_{AA})$ in the same Pb+Pb collisions and look into more accurate $p_T$-dependent energy loss based on the BDMPS formalism.