Dihadron azimuthal correlations in Au+Au collisions at {radical}(s{sub NN})=200 GeV
- University of Colorado, Boulder, Colorado 80309 (United States)
- Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow Region (Russian Federation)
- Columbia University, New York, New York 10027 (United States) and Nevis Laboratories, Irvington, New York 10533 (United States)
Azimuthal angle ({delta}{phi}) correlations are presented for a broad range of transverse momentum (0.4<p{sub T}<10 GeV/c) and centrality (0-92%) selections for charged hadrons from dijets in Au+Au collisions at {radical}(s{sub NN})=200 GeV. With increasing p{sub T}, the away-side {delta}{phi} distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons with p+p data suggest that the away-side distribution can be divided into a partially suppressed 'head' region centered at {delta}{phi}{approx}{pi}, and an enhanced 'shoulder' region centered at {delta}{phi}{approx}{pi}{+-}1.1. The p{sub T} spectrum for the associated hadrons in the head region softens toward central collisions. The spectral slope for the shoulder region is independent of centrality and trigger p{sub T}. The properties of the near-side distributions are also modified relative to those in p+p collisions, reflected by the broadening of the jet shape in {delta}{phi} and {delta}{eta}, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to p{sub T} < or approx. 4 GeV/c, above which both the hadron pair shape and per-trigger yield become similar to p+p collisions. These observations suggest that both the away- and near-side distributions contain a jet fragmentation component which dominates for p{sub T} > or approx. 5 GeV/c and a medium-induced component which is important for p{sub T} < or approx. 4 GeV/c. We also quantify the role of jets at intermediate and low p{sub T} through the yield of jet-induced pairs in comparison with binary scaled p+p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the p{sub T} magnitudes of the two hadrons) and is enhanced at low pair proxy energy. The former is consistent with jet quenching; the latter is consistent with the enhancement of soft hadron pairs due to transport of lost energy to lower p{sub T}.
- OSTI ID:
- 21192046
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 78, Issue 1; Other Information: DOI: 10.1103/PhysRevC.78.014901; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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