PHENIX Measurements of Reaction Plane Dependence of High-p_T Photons and Pions

Conference · Mon Jan 01 04:00:00 EST 2007

OSTI ID:931208

Pantuev, V. S. ^[1]; Awes, Terry C ^[2]; Batsouli, Sotiria ^[3]; Cianciolo, Vince ^[2]; Efremenko, Yuri ^[3]; Read, Jr, Kenneth F ^[2]; Silvermyr, David O ^[2]; Sorensen, Soren P ^[4]; Stankus, Paul W ^[2]; Young, Glenn R ^[2]; Zhang, Chun ^[3]

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1. University of Stony Brook, New York
2. ORNL
3. University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
4. University of Tennessee, Knoxville (UTK)

Direct photon and neutral pion production with respect to the reaction plane at high-p{sub T} were measured with the PHENIX experiment in Au+Au collisions at {radical}s{sub NN}=200 GeV at mid-rapidity. The azimuthal asymmetry parameter v{sub 2} for direct photons was found to be consistent with zero for all centrality classes. We evaluate the dependence of {pi}{sub 0} suppression at high-p{sub T} on the emission angle {Delta}{phi} with respect to the event reaction plane for seven centrality bins. For the peripheral bins we observe no suppression for neutral pions aligned with the reaction plane while {pi}{sup 0}'s produced perpendicular to the reaction plane are suppressed by factor 2. We found that a simple geometric picture can explain the observed suppression pattern.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931208
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
COLLISIONS
PHOTONS
PIONS
PRODUCTION
QUARK MATTER
TRANSVERSE MOMENTUM