PHENIX Measurements of Azimuthal Anisotropy for π0\pi^0 Production at High pTp_T in Au+Au Collisions at sNN=200\sqrt{s_{NN}}=200GeV

An improved measurement of $v_2$ for $\pi^0$ in a broad range of $p_T$ and centrality is presented. By combining $v_2$ with the $R_{AA}$, we provide new insights on jet-medium interactions. We show that current pQCD energy loss models cannot describe the suppression of the $\pi^0$ 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.Comment: 4 pages, 4 figures, 21st International Conference On Ultra-Relativistic Nucleus-Nucleus Collisions (QM2009) 30 Mar - 4 Apr 2009, Knoxville, Tennesse

High pTp_T Parton Energy Loss from Jet Pair Correlation Observables in the PHENIX Experiment

By tuning several experimental observables, such as momentum and reaction plane, the PHENIX experiment has performed a systematic study of high $p_T$ parton energy loss in hot nuclear matter, as well as jet induced medium modifications, such as the ridge and shoulder. Baseline d+Au measurements are also studied to provide the comparison as control of cold nuclear matter effect.Comment: 4 pages, 6 figures. To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee, with minor correctio