Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at √sNN=2.76 TeV

Adam, J. and Antičić, Tome and Erhardt, Filip and Gotovac, Sven and Mudnić, Eugen and Planinić, Mirko and Poljak, Nikola and Simatović, Goran and Utrobičić, Antonija and Vicković, Linda and Zyzak, M. (ALICE Collaboration) (2016) Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at √sNN=2.76 TeV. Journal of High Energy Physics, 2016 (9). pp. 164-40. ISSN 1029-8479

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Abstract

The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for π±, K± and p+p− in Pb-Pb collisions at √sNN=2.76 TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method, correlating the identified hadrons with reference particles from a different pseudorapidity region. Effects not related to the common event symmetry planes (non- flow) were estimated using correlations in pp collisions and were subtracted from the measurement. The obtained flow coefficients exhibit a clear mass ordering for transverse momentum (pT) values below ≈ 3 GeV/c. In the intermediate pT region (3< pT< 6 GeV/c), particles group at an approximate level according to the number of constituent quarks, suggesting that coalescence might be the relevant particle production mechanism in this region. The results for pT< 3 GeV/c are described fairly well by a hydrodynamical model (iEBE-VISHNU) that uses initial conditions generated by A Multi-Phase Transport model (AMPT) and describes the expansion of the fireball using a value of 0.08 for the ratio of shear viscosity to entropy density (η/s), coupled to a hadronic cascade model (UrQMD). Finally, expectations from AMPT alone fail to quantitatively describe the measurements for all harmonics throughout the measured transverse momentum region. However, the comparison to the AMPT model highlights the importance of the late hadronic rescattering stage to the development of the observed mass ordering at low values of pT and of coalescence as a particle production mechanism for the particle type grouping at intermediate values of pT for all harmonics.

Item Type: Article
Keywords: harmonic flow, identified hadrons, lead-lead
Date: September 2016
Subjects: NATURAL SCIENCES > Physics
Additional Information: Open Access, Copyright CERN, for the benefit of the ALICE Collaboration. Article funded by SCOAP3. Received: July 6, 2016. Revised: August 30, 2016. Accepted: September 20, 2016. Published: September 28, 2016.
Divisions: Faculty of Science > Department of Physics
Publisher: Springer
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 28 Oct 2017 17:57
Last Modified: 04 Nov 2018 13:06
URI: http://digre.pmf.unizg.hr/id/eprint/5631

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