### Session KG: Relativistic Heavy Ions: Au+Au

2:00 PM–5:15 PM, Thursday, September 22, 2005
Ritz-Carlton Hotel Room: Plantation 2

Chair: Hideki Hamagaki, University of Tokyo

Abstract ID: BAPS.2005.HAW.KG.11

### Abstract: KG.00011 : PHENIX measurements on High $p_T$ photon-hadron and $\pi^0$-hadron Azimuthal Correlations in $\sqrt{s_{NN}}=200$~GeV Au+Au Collisions

4:30 PM–4:45 PM

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#### Author:

Jiamin Jin
(Columbia University)

PHENIX has measured direct photon production in Au+Au collisions at $\sqrt{s_{NN}}=200$~GeV. Due to the suppression of high-$p_T$ pion production, a large photon excess over meson decay background is seen in central AuAu collisions at $p_T>6$GeV/c. This large direct photon signal allows us to use jets tagged by direct photons to probe the dense medium created in ultra- relativistic heavy-ion collisions at RHIC. Since photons interact with the medium much more weakly than hadrons, they will carry roughly the same amount of energy as the scattered quarks, thus providing a better measurement of the energy and direction of the away side jets. We will present the PHENIX results on the measurements of photon-hadron and $\pi^0$-hadron azimuthal correlations with the photon or $\pi^0$ momentum above 5 GeV/c. The results will be shown as a function of centrality and associated hadron $p_T$. By comparing the photon-hadron and $\pi^0$-hadron correlations, we will discuss the use of these two measurements to perform the first extraction of a direct photon-hardon correlation measurement at RHIC.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.HAW.KG.11