The azimuthal anisotropy of π0 production for 1<pT<18 GeV/c for Au+Au collisions at √sNN=200 GeV. has been measured. The observed anisotropy shows a gradual decrease for 3≲pT≲7–10 GeV/c, but remains positive beyond 10 GeV/c.
Calculations that implement a path-length dependence steeper than what is implied by current PQCD energy-loss models show reasonable agreement with the data.