skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: PHENIX Measurements of Reaction Plane Dependence of High-p T Photons and Pions

Abstract

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.

Authors:
 [1];  [2];  [3];  [2];  [3];  [2];  [2];  [4];  [2];  [2];  [3];  [5]
  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)
  5. The
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931208
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions: Quark Matter 2006, Shanghai, China, 20061114, 20061120
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; PHOTONS; PIONS; PRODUCTION; QUARK MATTER; COLLISIONS; TRANSVERSE MOMENTUM

Citation Formats

Pantuev, V. S., Awes, Terry C, Batsouli, Sotiria, Cianciolo, Vince, Efremenko, Yuri, Read Jr, Kenneth F, Silvermyr, David O, Sorensen, Soren P, Stankus, Paul W, Young, Glenn R, Zhang, Chun, and PHENIX, Collaboration. PHENIX Measurements of Reaction Plane Dependence of High-pT Photons and Pions. United States: N. p., 2007. Web.
Pantuev, V. S., Awes, Terry C, Batsouli, Sotiria, Cianciolo, Vince, Efremenko, Yuri, Read Jr, Kenneth F, Silvermyr, David O, Sorensen, Soren P, Stankus, Paul W, Young, Glenn R, Zhang, Chun, & PHENIX, Collaboration. PHENIX Measurements of Reaction Plane Dependence of High-pT Photons and Pions. United States.
Pantuev, V. S., Awes, Terry C, Batsouli, Sotiria, Cianciolo, Vince, Efremenko, Yuri, Read Jr, Kenneth F, Silvermyr, David O, Sorensen, Soren P, Stankus, Paul W, Young, Glenn R, Zhang, Chun, and PHENIX, Collaboration. Mon . "PHENIX Measurements of Reaction Plane Dependence of High-pT Photons and Pions". United States. doi:.
@article{osti_931208,
title = {PHENIX Measurements of Reaction Plane Dependence of High-pT Photons and Pions},
author = {Pantuev, V. S. and Awes, Terry C and Batsouli, Sotiria and Cianciolo, Vince and Efremenko, Yuri and Read Jr, Kenneth F and Silvermyr, David O and Sorensen, Soren P and Stankus, Paul W and Young, Glenn R and Zhang, Chun and PHENIX, Collaboration},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • We report on the distributions of charged particles produced in association with high p/sub T/ prompt photons and neutral pions in pp collisions at ..sqrt.. s = 63 GeV and theta = 90/sup 0/ in the centre of mass. We find photons to be relatively unaccompained by other particles at small angles with respect to the photon, and thereby extract a measurement of the fraction of prompt photons due to bremsstrahlung production. The relative density of positive to negative particles in the system recoiling from the photon has been measured and compared with QCD motivated calculations.
  • Direct photon spectra measured at small p{sub T} in p+p, d+Au and Au+Au collisions at {radical}s{sub NN}=200 GeV are presented. Several measurement techniques including statistical subtraction, tagging, and internal and external conversion were applied and found to produce consistent results. The p+p and d+Au results are found to be in very good agreement with pQCD predictions over the entire p{sub T} range. The direct photon yield in Au+Au collisions is compared to binary scaled d+Au data but the large systematic errors in d+Au results do not allow us to draw conclusions on the presence of a direct photon excess duemore » to matter-related emission in Au+Au collisions.« less
  • High-p{sub T} hadron-hadron correlations have been measured with the PHENIX experiment in Cu and pp collisions at {radical}s{sub NN}=200 GeV. A comparison of the jet widths and yields between the two colliding systems allows us to study the medium effect on jets. We also present a first measurement of direct photon-hadron correlations in Au and pp collisions. We find that the near-side yields are consistent with zero in both systems. By comparing the jet yields on the away side, we observe a suggestion of the expected suppression of hadrons associated with photons in Au collisions.
  • Measurements of inclusive spectra of hadrons at large transverse momentum over a broad range of energy in different collision systems have been performed with the PHENIX experiment at RHIC. The data allow us to study the energy and system size dependence of the suppression observed in R{sub AA} of high-p{sub T} hadrons at {radical}s{sub NN} = 200 GeV. Due to the large energy range from {radical}s{sub NN} = 22 GeV to 200 GeV, the results can be compared to results from CERN SPS at a similar energy. The large Au+Au dataset from the 2004 run of RHIC also allows usmore » to constrain theoretical models that describe the hot and dense matter produced in such collisions. Investigation of particle ratios such as {eta}/{pi}{sup 0} helps in understanding the mechanisms of energy loss.« less
  • Particle-type dependences of hadron yield suppression/enhancement patterns, especially its difference between mesons and baryons, at intermediate p{sub T} (2-5 GeV/c) is one of the findings in heavy ion collisions at RHIC. A systematic study of identified hadron production was performed in Au+Au/Cu+Cu collisions at {radical}s{sub NN} = 62.4/200 GeV, to investigate the possible origins of this difference. In this paper, we show particle ratios, nuclear modification factors and their scaling properties.