Dihadron Azimuthal Correlations in Au+Au Collisions at s_NN = 200 GeV
- University of Colorado, Boulder
- ORNL
- University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
- University of Tennessee, Knoxville (UTK)
Azimuthal angle ({Delta}{sup {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}{sup {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}{sup {phi}} {approx} {pi}, and an enhanced 'shoulder' region centered at {Delta}{sup {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}{sup {phi}} and {Delta}{sup {eta}}, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to p{sub T} {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} {approx}> 5 GeV/c and a medium-induced component which is important for p{sub T} {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}.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 934939
- Journal Information:
- Physical Review C, Vol. 78, Issue 1
- Country of Publication:
- United States
- Language:
- English
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