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Article
Neutral pion production with respect to centrality and reaction plane in Au plus Au collisions at root S-NN=200 GeV
Physical Review C
  • Andrew Adare, University of Colorado, Boulder
  • John C. Hill, Iowa State University
  • Todd Kempel, Iowa State University
  • John G. Lajoie, Iowa State University
  • Alexandre Lebedev, Iowa State University
  • Craig Ogilvie, Iowa State University
  • H. Pei, Iowa State University
  • Marzia Rosati, Iowa State University
  • Alexey Yu. Semenov, Iowa State University
  • Carla Vale, Iowa State University
  • Feng Wei, Iowa State University
  • et al.
  • PHENIX Collaboration, PHENIX Collaboration
Document Type
Article
Disciplines
Publication Version
Published Version
Publication Date
3-28-2013
DOI
10.1103/PhysRevC.87.034911
Abstract
The PHENIX experiment has measured the production of pi(0)s in Au + Au collisions at root S-NN = 200 GeV. The new data offer a fourfold increase in recorded luminosity, providing higher precision and a larger reach in transverse momentum, p(T), to 20 GeV/c. The production ratio of eta/pi(0) is 0.46 +/- 0.01(stat) +/- 0.05(syst), constant with p(T) and collision centrality. The observed ratio is consistent with earlier measurements, as well as with the p + p and d + Au values. pi(0) are suppressed by a factor of 5, as in earlier findings. However, with the improved statistical precision a small but significant rise of the nuclear modification factor R-AA vs p(T), with a slope of 0.0106 +/-(0.0034)(0.0029) (Gev/c)(-1), is discernible in central collisions. A phenomenological extraction of the average fractional parton energy loss shows a decrease with increasing p(T). To study the path-length dependence of suppression, the pi(0) yield is measured at different angles with respect to the event plane; a strong azimuthal dependence of the pi(0) R-AA is observed. The data are compared to theoretical models of parton energy loss as a function of the path length L in the medium. Models based on perturbative quantum chromodynamics are insufficient to describe the data, while a hybrid model utilizing pQCD for the hard interactions and anti-de-Sitter space/conformal field theory (AdS/CFT) for the soft interactions is consistent with the data.
Comments

This is an article from Physical Review C 87 (2013): 034911-1, doi:10.1103/PhysRevC.87.034911. Posted with permission.

Copyright Owner
American Physical Society
Language
en
File Format
application/pdf
Citation Information
Andrew Adare, John C. Hill, Todd Kempel, John G. Lajoie, et al.. "Neutral pion production with respect to centrality and reaction plane in Au plus Au collisions at root S-NN=200 GeV" Physical Review C Vol. 87 Iss. 3 (2013) p. 034911
Available at: http://works.bepress.com/craig-ogilvie/93/