PHENIX Measurements of Azimuthal Anisotropy for π0 Production at High pT in Au+Au Collisions at

An improved measurement of ν2 for π0 in a broad range of pT and centrality is presented. By combining ν2 with the RAA, we provide new insights on jet-medium interactions. We show that current pQCD energy loss models cannot describe the suppression of the π0 as a function of the angle with respect to the reaction plane. Our result could help to resolve the factor of 4 differences in the predicted transport coefficients among these models. Alternatively, it may suggest that non-perturbative effects associated with the strongly coupled QGP are important, and new theoretical developments are needed to fully understand the jet medium interactions.