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Study of Jet Quench via Azimuthal Anisotropies with PID

Large azimuthal anisotropies $ v_2$ are also one of the exciting discoveries from RHIC. Compared with collisions at lower energies, $ v_2$ observed at RHIC is found to be larger, which suggests quicker thermalization; much quicker than what is expected from ordinal hadronic rescatterings. Thus the large $ v_2$ implies other ingredients for thermalization than hadrons. As shown in Fig.4, dependence on transverse momentum provides important clue to understand the mechanism. At lower $ p_T$ region, split of pion/kaon/proton which is consistent with hydrodynalical flow picture, has been seen while at higher $ p_T$ clear departure from the hydrodynamic behaviour has been observed. Above 2 GeV/c, the way it depart from the hydrodynamic behaviour is considered to depend on the jet quench effects and/or gluon densities. Extension of PID capability will enable us to study these phenomena at higher $ p_T$ region where observables might have more sensitivities on jet physics.

図 4: Azimuthal anisotropies in Au+Au at $ \sqrt {s_{NN}}$ = 200 GeV with PID [left] for negative, and [middle] for positive [shown at QM2002, (PHENIX)] and [right] theoretical predictions based on jet quench scenario [M. Gyulassy et al.,Phys.Lett.B526(2002)301.].
\includegraphics[width=0.6\linewidth,height=64mm]{figs/esumi-v2.eps} \includegraphics[width=0.3\linewidth,height=60mm]{figs/Gyu-pi-p-v2.eps}


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次へ: Study of Jet Quench 上へ: Physics Motivations 戻る: Study of Jet Quench   目次
Yasuo Miake 平成14年10月23日