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Title: Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN)=200 GeV

Publication Date:
Research Org.:
ORNL Oak Ridge National Laboratory
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
Journal ID: 0031-9007
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 91
Country of Publication:
United States

Citation Formats

Adler, S.S.. Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN)=200 GeV. United States: N. p., 2003. Web. doi:10.1103/PhysRevLett.91.182301.
Adler, S.S.. Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN)=200 GeV. United States. doi:10.1103/PhysRevLett.91.182301.
Adler, S.S.. 2003. "Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN)=200 GeV". United States. doi:10.1103/PhysRevLett.91.182301.
title = {Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN)=200 GeV},
author = {Adler, S.S.},
abstractNote = {},
doi = {10.1103/PhysRevLett.91.182301},
journal = {Physical Review Letters},
number = ,
volume = 91,
place = {United States},
year = 2003,
month =
  • Here, the elliptic flow coefficient (v 2) of identified particles in Pb-Pb collisions at √s NN =2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of |Δη| > 0.9 between the identified hadron under study and the reference particles. The v 2 is reported for π ±, K ±, K S 0, p+p¯, Φ, Λ+Λ¯, Ξ –+Ξ¯+ and Ω ¯+ in several collision centralities. In the low transverse momentum (p T) region, p T < 3 GeV/c,more » v 2(p T) exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for π± and the combined K ± and K S 0 results, are described fairly well by hydrodynamic calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the v 2(p T) for p+p¯, Φ, Λ+Λ¯ and Ξ ¯+. For transverse momentum values larger than about 3 GeV/c, particles tend to group according to their type, i.e. mesons and baryons. The present measurements exhibit deviations from the number of constituent quark (NCQ) scaling at the level of ±20% for p T > 3 GeV/c.« less
  • Differential measurements of the elliptic (v{sub 2}) and hexadecapole (v{sub 4}) Fourier flow coefficients are reported for charged hadrons as a function of transverse momentum (p{sub T}) and collision centrality or number of participant nucleons (N{sub part}) for Au+Au collisions at {radical}s{sub NN} = 200 GeV. The v{sub 2,4} measurements at pseudorapidity |{eta}| {le} 0.35, obtained with four separate reaction-plane detectors positioned in the range 1.0 < |{eta}| < 3.9, show good agreement, indicating the absence of significant {Delta}{eta}-dependent nonflow correlations. Sizable values for v{sub 4}(p{sub T}) are observed with a ratio v{sub 4}(p{sub T},N{sub part})/v{sub 2}{sup 2}(p{sub T},N{sub part})more » {approx} 0.8 for 50 {le} N{sub part} {le} 200, which is compatible with the combined effects of a finite viscosity and initial eccentricity fluctuations. For N{sub part} {ge} 200 this ratio increases up to 1.7 in the most central collisions.« less
  • Differential elliptic flow (v{sub 2}) for {phi} mesons and (anti)deuterons ({bar d})d is measured for Au+Au collisions at {radical}s{sub NN}=200 GeV. The v{sub 2} for {phi} mesons follows the trend of lighter {pi}{sup {+-}} and K{sup {+-}} mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v{sub 2} values for ({bar d})d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v{sub 2} per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.
  • We present inclusive charged hadron elliptic flow (v{sub 2}) measured over the pseudorapidity range |{eta}| < 0.35 in Au+Au collisions at {radical}s{sub NN} = 200 GeV. Results for v{sub 2} are presented over a broad range of transverse momentum (p{sub T} = 0.2-8.0 GeV/c) and centrality (0-60%). To study nonflow effects that are correlations other than collective flow, as well as the fluctuations of v{sub 2}, we compare two different analysis methods: (1) the event-plane method from two independent subdetectors at forward (|{eta}| = 3.1-3.9) and beam (|{eta}| > 6.5) pseudorapidities and (2) the two-particle cumulant method extracted using correlationsmore » between particles detected at midrapidity. The two event-plane results are consistent within systematic uncertainties over the measured p{sub T} and in centrality 0-40%. There is at most a 20% difference in the v{sub 2} between the two event-plane methods in peripheral (40-60%) collisions. The comparisons between the two-particle cumulant results and the standard event-plane measurements are discussed.« less