### Session FF: Mini-Symposium: Viscosity, String Theory and Hydrodynamics

8:30 AM–10:30 AM, Saturday, October 25, 2008
Room: Simmons Ballroom 4

Chair: W.A. Zajc, Columbia University

Abstract ID: BAPS.2008.DNP.FF.4

### Abstract: FF.00004 : Measurements of High $p_{T}$ Identified Hadron $v_{2}$ in Au+Au Collisions at $\sqrt{S_{NN}}$ = 200 GeV by the PHENIX Experiment

9:30 AM–9:42 AM

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#### Author:

Shengli Huang
(PHENIX Collaboration)

Measurements of the elliptic flow $v_{2}$ at RHIC have provided sensitive information about the earliest stages dynamics of heavy ion collisions. The $v_{2}$ of identified hadrons has been found empirically to scale with the number of constituent quarks at low $p_{T}$, providing evidence that partonic degrees of freedom determine the early dynamics of the system. The measurement of high $p_{T}$ identified hadrons $v_{2}$ will allow us to further test this scaling. It will provide the information on the limits of applicability of the hydrodynamic description of the system dynamics. The difference of $v_{2}$ between the $K^{+}$, $K^{-}$ and the proton, anti-proton at high $p_{T}$ will also provide the information about the particle production and dynamics mechanism. In that the $K^{-}$ and anti-proton are mainly from gluon fragmentation, while the $K^{+}$ and proton are mainly from light quark fragmentation. In this talk, we will present measurements of pion, kaon and proton $v_{2}$ to $p_T$ of 6GeV/c as a function of centrality in Au + Au collisions at $\sqrt{S_{NN}}$ = 200 GeV. The constituent quark scaling will be tested by these new measurements in the different centrality bins. The $v_{2}$ difference between the $K^{+}$ , $K^{-}$ and the proton, anti-proton will also be studied as a function of $p_{T}$ and centrality.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.DNP.FF.4