Systematic studies of correlations between different order flow harmonics in Pb-Pb collisions at √sNN = 2.76 TeV

Acharya, S. and Antičić, Tome and Erhardt, Filip and Gotovac, Sven and Jerčić, Marko and Lončar, P. and Mudnić, Eugen and Planinić, Mirko and Poljak, Nikola and Simatović, Goran and Utrobičić, Antonija and Vicković, Linda and Zou, S. (ALICE Collaboration) (2018) Systematic studies of correlations between different order flow harmonics in Pb-Pb collisions at √sNN = 2.76 TeV. Physical Review C, 97 (2). pp. 24906-23. ISSN 2469-9985

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The correlations between event-by-event fluctuations of anisotropic flow harmonic amplitudes have been measured in Pb-Pb collisions at √sNN = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The results are reported in terms of multiparticle correlation observables dubbed symmetric cumulants. These observables are robust against biases originating from nonflow effects. The centrality dependence of correlations between the higher order harmonics (the quadrangular v4 and pentagonal v5 flow) and the lower order harmonics (the elliptic v2 and triangular v3 flow) is presented. The transverse momentum dependences of correlations between v3 and v2 and between v4 and v2 are also reported. The results are compared to calculations from viscous hydrodynamics and a multiphase transport (AMPT) model calculations. The comparisons to viscous hydrodynamic models demonstrate that the different order harmonic correlations respond differently to the initial conditions and the temperature dependence of the ratio of shear viscosity to entropy density (η/s). A small average value of η/s is favored independent of the specific choice of initial conditions in the models. The calculations with the AMPT initial conditions yield results closest to the measurements. Correlations among the magnitudes of v2, v3, and v4 show moderate pT dependence in midcentral collisions. This might be an indication of possible viscous corrections to the equilibrium distribution at hadronic freeze-out, which might help to understand the possible contribution of bulk viscosity in the hadronic phase of the system. Together with existing measurements of individual flow harmonics, the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions.

Item Type: Article
Date: 2018
Subjects: NATURAL SCIENCES > Physics
Additional Information: ©2018 CERN, for the ALICE Collaboration. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Received 1 October 2017; published 12 February 2018.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 20 Mar 2018 16:45
Last Modified: 20 Mar 2018 16:45

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