Azimuthal Anisotropy of π0 Production in Au+Au Collisions at sNN=200GeV: Path-Length Dependence of Jet Quenching and the Role of Initial Geometry
Abstract
We have measured the azimuthal anisotropy of π0 production for 1<pT<18GeV/c for Au+Au collisions at sNN=200GeV. The observed anisotropy shows a gradual decrease for 3≲pT≲7-10GeV/c, but remains positive beyond 10GeV/c. The magnitude of this anisotropy is underpredicted, up to at least ∼10GeV/c, by current perturbative QCD (PQCD) energy-loss model calculations. An estimate of the increase in anisotropy expected from initial-geometry modification due to gluon saturation effects and fluctuations is insufficient to account for this discrepancy. Calculations that implement a path-length dependence steeper than what is implied by current PQCD energy-loss models show reasonable agreement with the data.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2010
- DOI:
- arXiv:
- arXiv:1006.3740
- Bibcode:
- 2010PhRvL.105n2301A
- Keywords:
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- 25.75.Dw;
- Particle and resonance production;
- Nuclear Experiment
- E-Print:
- 384 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.html