Azimuthal Anisotropy of {pi}{sup 0} Production in Au+Au Collisions at {radical}(s{sub NN})=200 GeV: Path-Length Dependence of Jet Quenching and the Role of Initial Geometry

Journal Article · Fri Oct 01 00:00:00 EDT 2010 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.105.142301· OSTI ID:21466986

Adare, A; Bickley, A A; Ellinghaus, F; Glenn, A; Kinney, E; Kiriluk, K; Linden Levy, L A; Nagle, J L; Rosen, C A; Seele, J; Wysocki, M ^[1]; Afanasiev, S; Isupov, A; Litvinenko, A; Malakhov, A; Peresedov, V; Rukoyatkin, P; Zolin, L ^[2]; Aidala, C; Datta, A ^[3]

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1. University of Colorado, Boulder, Colorado 80309 (United States)
2. Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation)
3. Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003-9337 (United States)

We have measured the azimuthal anisotropy of {pi}{sup 0} production for 1<p{sub T}<18 GeV/c for Au+Au collisions at {radical}(s{sub NN})=200 GeV. The observed anisotropy shows a gradual decrease for 3 < or approx. p{sub T} < or approx.l 7-10 GeV/c, but remains positive beyond 10 GeV/c. The magnitude of this anisotropy is underpredicted, up to at least {approx}10 GeV/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.

• OSTI ID: 21466986
• Journal Information: Physical Review Letters, Vol. 105, Issue 14; Other Information: DOI: 10.1103/PhysRevLett.105.142301; (c) 2010 American Institute of Physics; ISSN 0031-9007
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
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PARTICLE PRODUCTION
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