Energy dependence and fluctuations of anisotropic fow in Pb-Pb collisions at root s(NN)=5:02 and 2:76 TeV



Acharya, S, Acosta, FT, Adamova, D, Adolfsson, J, Aggarwal, MM, Rinella, G Aglieri, Agnello, M, Agrawal, N, Ahammed, Z, Ahn, SU
et al (show 994 more authors) (2018) Energy dependence and fluctuations of anisotropic fow in Pb-Pb collisions at root s(NN)=5:02 and 2:76 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2018 (7). 103-.

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title> <jats:p>Measurements of anisotropic flow coefficients with two- and multi-particle cumulants for inclusive charged particles in Pb-Pb collisions at <jats:inline-formula> <jats:alternatives> <jats:tex-math>$$ \sqrt{s_{\mathrm{NN}}}=5.02 $$</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mi>N</mml:mi> <mml:mi>N</mml:mi> </mml:mrow> </mml:msub> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>5.02</mml:mn> </mml:math> </jats:alternatives> </jats:inline-formula> and 2.76 TeV are reported in the pseudorapidity range |<jats:italic>η</jats:italic>| &lt; 0.8 and transverse momentum 0.2 &lt; <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> &lt; 50 GeV/<jats:italic>c</jats:italic>. The full data sample collected by the ALICE detector in 2015 (2010), corresponding to an integrated luminosity of 12.7 (2.0) <jats:italic>μ</jats:italic>b<jats:sup>−1</jats:sup> in the centrality range 0-80%, is analysed. Flow coefficients up to the sixth flow harmonic (<jats:italic>v</jats:italic> <jats:sub>6</jats:sub>) are reported and a detailed comparison among results at the two energies is carried out. The <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> dependence of anisotropic flow coefficients and its evolution with respect to centrality and harmonic number <jats:italic>n</jats:italic> are investigated. An approximate power-law scaling of the form <jats:italic>v</jats:italic> <jats:sub> <jats:italic>n</jats:italic> </jats:sub>(<jats:italic>p</jats:italic> <jats:sub>T</jats:sub>) ∼ <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> <jats:sup> <jats:italic>n</jats:italic>/3</jats:sup> is observed for all flow harmonics at low <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> (0.2 &lt; <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> &lt; 3 GeV/<jats:italic>c</jats:italic>). At the same time, the ratios <jats:italic>v</jats:italic> <jats:sub> <jats:italic>n</jats:italic> </jats:sub>/<jats:italic>v</jats:italic> <jats:sub> <jats:italic>m</jats:italic> </jats:sub> <jats:sup> <jats:italic>n</jats:italic>/ <jats:italic>m</jats:italic> </jats:sup> are observed to be essentially independent of <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> for most centralities up to about <jats:italic>p</jats:italic> <jats:sub>T</jats:sub> = 10 GeV/<jats:italic>c</jats:italic>. Analysing the differences among higher-order cumulants of elliptic flow (<jats:italic>v</jats:italic> <jats:sub>2</jats:sub>), which have different sensitivities to flow fluctuations, a measurement of the standardised skewness of the event-by-event <jats:italic>v</jats:italic> <jats:sub>2</jats:sub> distribution <jats:italic>P</jats:italic>(<jats:italic>v</jats:italic> <jats:sub>2</jats:sub>) is reported and constraints on its higher moments are provided. The Elliptic Power distribution is used to parametrise <jats:italic>P</jats:italic>(<jats:italic>v</jats:italic> <jats:sub>2</jats:sub>), extracting its parameters from fits to cumulants. The measurements are compared to different model predictions in order to discriminate among initial-state models and to constrain the temperature dependence of the shear viscosity to entropy-density ratio. </jats:p>

Item Type: Article
Uncontrolled Keywords: Heavy Ion Experiments
Depositing User: Symplectic Admin
Date Deposited: 01 May 2019 10:52
Last Modified: 14 Mar 2024 21:18
DOI: 10.1007/JHEP07(2018)103
Open Access URL: https://doi.org/10.1007/JHEP07(2018)103
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3039209