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

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.