Study of J/psi azimuthal anisotropy at forward rapidity in Pb-Pb collisions at root s(NN)=5.02 TeV

The ALICE Collaboration, S. Acharya, E. J. Brücken, B. Chang, T. E. Hilden, D. J. Kim, V. Litichevskyi, M. M. Mieskolainen, R. Orava, J. E. Parkkila, J. Rak, S. S. Räsänen, S. Saarinen, M. Slupecki, T. W. Snellman, W. H. Trzaska, M. Vargyas, J. Viinikainen

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The second (v(2)) and third (v(3)) flow harmonic coefficients of J/ mesons are measured at forward rapidity (2.5 < y < 4.0) in Pb-Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC. Results are obtained with the scalar product method and reported as a function of transverse momentum, p(T), for various collision centralities. A positive value of J/ v(3) is observed with 3.7 sigma significance. The measurements, compared to those of prompt D-0 mesons and charged particles at mid-rapidity, indicate an ordering with v(n)(J/) < v(n)(D-0) < v(n)(h(+/-)) (n = 2, 3) at low and intermediate p(T) up to 6 GeV/c and a convergence with v(2)(J/) approximate to v(2)(D-0) approximate to v(2)(h(+/-)) at high p(T) above 6-8 GeV/c. In semi-central collisions (5-40% and 10-50% centrality intervals) at intermediate p(T) between 2 and 6 GeV/c, the ratio v(3)/v(2) of J/ mesons is found to be significantly lower (4.6 sigma) with respect to that of charged particles. In addition, the comparison to the prompt D-0-meson ratio in the same p(T) interval suggests an ordering similar to that of the v(2) and v(3) coefficients. The J/ v(2) coefficient is further studied using the Event Shape Engineering technique. The obtained results are found to be compatible with the expected variations of the eccentricity of the initial-state geometry.
Original languageEnglish
Article number012
JournalJournal of High Energy Physics
Issue number2
Number of pages30
Publication statusPublished - 4 Feb 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences
  • Hadron-Hadron scattering (experiments)
  • FLOW

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