Effects of flow fluctuations and partial thermalization on $v_4$

Abstract

The second and fourth Fourier harmonic of the azimuthal distribution of particles, $v_2$ and $v_4$, have been measured in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The harmonic $v_4$ is mainly induced from $v_2$ as a higher-order effect. However, the ratio $v_4/(v_2{)}^2$ is significantly larger than predicted by hydrodynamics. Effects of partial thermalization are estimated on the basis of a transport calculation, and are shown to increase $v_4/(v_2{)}^2$ by a small amount. We argue that the large value of $v_4/(v_2{)}^2$ seen experimentally is mostly due to elliptic flow fluctations. However, the standard model of eccentricity fluctuations is unable to explain the large magnitude of $v_4/(v_2{)}^2$ in central collisions.

9 pages

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Cited by in corpus (36)

• Measurements of Higher-Order Flow Harmonics in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Triangular flow in hydrodynamics and transport theory
• Mapping the hydrodynamic response to the initial geometry in heavy-ion collisions
• Non linearities in the harmonic spectrum of heavy ion collisions with ideal and viscous hydrodynamics
• Translation of collision geometry fluctuations into momentum anisotropies in relativistic heavy-ion collisions
• Event-by-event hydrodynamics and elliptic flow from fluctuating initial state
• Measurement of higher-order harmonic azimuthal anisotropy in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV
• Eliminating experimental bias in anisotropic-flow measurements of high-energy nuclear collisions
• Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at $\sqrt{{\text{s}}_{\text{NN}}}=5.02$ and $2.76$ TeV
• $v_4$, $v_5$, $v_6$, $v_7$: nonlinear hydrodynamic response versus LHC data
• Elliptic and hexadecapole flow of charged hadrons in Au+Au collisions at sqrt(s_NN) = 200 GeV
• Anisotropic flow in event-by-event ideal hydrodynamic simulations of sqrt(s_{NN})=200 GeV Au+Au collisions
• Principal component analysis of event-by-event fluctuations
• Initial eccentricity fluctuations and their relation to higher-order flow harmonics
• Non-Gaussian elliptic-flow fluctuations in PbPb collisions at $\sqrt{s_{{}_{\text{NN}}}}=$ 5.02 TeV
• v4 from ideal and viscous hydrodynamic simulations of nuclear collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC)
• Constraining the viscous freeze-out distribution function with data obtained at the BNL Relativistic Heavy Ion Collider (RHIC)
• Hexagonal flow v_6 as a superposition of elliptic v_2 and triangular v_3 flows
• Decomposition of fluctuating initial conditions and flow harmonics
• Azimuthal anisotropy of pi^0 and eta mesons in Au+Au collisions at sqrt(s_NN)=200 GeV
• Phenomenology of the little bang
• Effect of jets on $v_4/v_2^2$ ratio and constituent quark scaling in relativistic heavy-ion collisions
• Effect of initial fluctuations on the collective flow in intermediate-energy heavy ion collisions
• The enhancement of $v_4$ in nuclear collisions at the highest densities signals a first order phase transition
• Glauber-based evaluations of the odd moments of the initial eccentricity relative to the even order participant planes
• Dissipative corrections to particle spectra and anisotropic flow from a saddle-point approximation to kinetic freeze out
• Constraints on models for the initial collision geometry in ultra relativistic heavy ion collisions
• Investigating the scaling of higher-order flows in relativistic heavy-ion collisions
• Dependence on beam energy and nuclear equation of state dependence of anisotropic flow and particle production in low-energy heavy-ion collisions
• Anisotropic flow of charged and identified hadrons at FAIR energies and its dependence on the nuclear equation of state
• v4 for identified particles at RHIC from viscous hydrodynamics
• Detail study of the medium created in Au+Au collisions with high $p_T$ probes by the PHENIX experiment at RHIC
• Are eccentricity fluctuations able to explain the centrality dependence of $v_4$?
• Effect of various particlization scenarios on anisotropic flow and particle production using UrQMD hybrid model
• Why is $v_4/(v_2{)}^2$ larger than predicted by hydrodynamics?
• $\Delta \eta$-$\Delta \varphi$ correlations and the ridge structure in STAR