Fluctuations of anisotropic flow in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector

Abstract

Multi-particle azimuthal cumulants are measured as a function of centrality and transverse momentum using 470 $\mu$b${}^{-1}$ of Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of harmonic flow coefficients $v_n$ and correlated fluctuations between two harmonics $v_n$ and $v_m$. For the first time, a non-zero four-particle cumulant is observed for dipolar flow, $v_1$. The four-particle cumulants for elliptic flow, $v_2$, and triangular flow, $v_3$, exhibit a strong centrality dependence and change sign in ultra-central collisions. This sign change is consistent with significant non-Gaussian fluctuations in $v_2$ and $v_3$. The four-particle cumulant for quadrangular flow, $v_4$, is found to change sign in mid-central collisions. Correlations between two harmonics are studied with three- and four-particle mixed-harmonic cumulants, which indicate an anti-correlation between $v_2$ and $v_3$, and a positive correlation between $v_2$ and $v_4$. These correlations decrease in strength towards central collisions and either approach zero or change sign in ultra-central collisions. To investigate the possible flow fluctuations arising from intrinsic centrality or volume fluctuations, the results are compared between two different event classes used for centrality definitions. In peripheral and mid-central collisions where the cumulant signals are large, only small differences are observed. In ultra-central collisions, the differences are much larger and transverse momentum dependent. These results provide new information to disentangle flow fluctuations from the initial and final states, as well as new insights on the influence of centrality fluctuations.

arXiv comment59 pages in total, author list starting page 43, 36 figures, published by Journal of High Energy Physics. All figures including auxiliary figures can be found at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2017-09/

References in corpus (70)

• The ATLAS Simulation Infrastructure
• Glauber Modeling in High Energy Nuclear Collisions
• Collective flow and viscosity in relativistic heavy-ion collisions
• Performance of the ATLAS Trigger System in 2015
• HIJING 1.0: A Monte Carlo Program for Parton and Particle Production in High Energy Hadronic and Nuclear Collisions
• Heavy Ion Collisions: The Big Picture, and the Big Questions
• Hydrodynamic Modeling of Heavy-Ion Collisions
• Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV
• Event-by-event anisotropic flow in heavy-ion collisions from combined Yang-Mills and viscous fluid dynamics
• Multiplicity and transverse-momentum dependence of two- and four-particle correlations in pPb and PbPb collisions
• Measurement of the azimuthal anisotropy for charged particle production in sqrt(s_NN) = 2.76 TeV lead-lead collisions with the ATLAS detector
• Flow analysis with cumulants: direct calculations
• Triangularity and Dipole Asymmetry in Heavy Ion Collisions
• Flow analysis from multiparticle azimuthal correlations
• Elliptic flow from two- and four-particle correlations in Au + Au collisions at sqrt{s_{NN}} = 130 GeV
• Measurements of Higher-Order Flow Harmonics in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead-lead collisions at sqrt(s_NN) = 2.76 TeV with the ATLAS detector
• Mapping the hydrodynamic response to the initial geometry in heavy-ion collisions
• New method for measuring azimuthal distributions in nucleus-nucleus collisions
• Event-by-event distributions of azimuthal asymmetries in ultrarelativistic heavy-ion collisions
• The Importance of Correlations and Fluctuations on the Initial Source Eccentricity in High-Energy Nucleus-Nucleus Collisions
• Generic framework for anisotropic flow analyses with multi-particle azimuthal correlations
• Measurement of the distributions of event-by-event flow harmonics in lead--lead collisions at sqrt(s_NN)=2.76 TeV with the ATLAS detector at the LHC
• Non linearities in the harmonic spectrum of heavy ion collisions with ideal and viscous hydrodynamics
• Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
• Measurement of event-plane correlations in sqrt(s_NN)=2.76 TeV lead-lead collisions with the ATLAS detector
• Correlated event-by-event fluctuations of flow harmonics in Pb-Pb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV
• Measurement of higher-order harmonic azimuthal anisotropy in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV
• Volume fluctuations and higher order cumulants of the net baryon number
• Measurement of charged-particle spectra in Pb+Pb collisions at $\sqrt{s_{\mathsf{NN}}}=2.76$ TeV with the ATLAS detector at the LHC
• The ATLAS Inner Detector commissioning and calibration
• Hydrodynamic event-plane correlations in Pb+Pb collisions at sqrt(s)=2.76ATeV
• Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead-lead collisions at sqrt(s_NN) = 2.76 TeV with the ATLAS detector
• Azimuthal anisotropy in U+U and Au+Au collisions at RHIC
• Investigations of anisotropic flow using multi-particle azimuthal correlations in pp, p-Pb, Xe-Xe, and Pb-Pb collisions at the LHC
• Fluctuating flow angles and anisotropic flow measurements
• Measurement of multi-particle azimuthal correlations in $pp$, $p$+Pb and low-multiplicity Pb+Pb collisions with the ATLAS detector
• Measurement of the correlation between flow harmonics of different order in lead-lead collisions at $\sqrt{s_{NN}}$=2.76 TeV with the ATLAS detector
• Evidence of sub-nucleonic degrees of freedom in J/$\psi$ photoproduction in ultraperipheral collisions at the CERN Large Hadron Collider
• Breaking of factorization of two-particle correlations in hydrodynamics
• Volume Fluctuation and Autocorrelation Effects in the Moment Analysis of Net-proton Multiplicity Distributions in Heavy-Ion Collisions
• Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at $\sqrt{{\text{s}}_{\text{NN}}}=5.02$ and $2.76$ TeV
• Revealing long-range multi-particle collectivity in small collision systems via subevent cumulants
• A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion
• Universal fluctuation-driven eccentricities in proton-proton, proton-nucleus and nucleus-nucleus collisions
• Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV in PbPb collisions at sqrt(s[NN]) = 5.02 TeV
• Measurement of longitudinal flow de-correlations in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ and 5.02 TeV with the ATLAS detector
• Measurement of multi-particle azimuthal correlations with the subevent cumulant method in $pp$ and $p$+Pb collisions with the ATLAS detector at the LHC
• Measurement of flow harmonics with multi-particle cumulants in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV with the ATLAS detector
• Extracting the shear viscosity of the quark-gluon plasma from flow in ultra-central heavy-ion collisions
• Relative flow fluctuations as a probe of initial state fluctuations
• Plane correlations and hydrodynamic simulations of heavy ion collisions
• Event-shape fluctuations and flow correlations in ultra-relativistic heavy-ion collisions
• Effects of momentum conservation on the analysis of anisotropic flow
• Correlations of flow harmonics in 2.76A TeV Pb--Pb collisions
• Symmetric cumulants and event-plane correlations in Pb+Pb collisions
• Non-Gaussian elliptic-flow fluctuations in PbPb collisions at $\sqrt{s_{{}_{\text{NN}}}}=$ 5.02 TeV
• Relating centrality to impact parameter in nucleus-nucleus collisions
• Systematic studies of correlations between different order flow harmonics in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Energy and system-size dependence of two- and four-particle $v_2$ measurements in heavy-ion collisions at RHIC and their implications on flow fluctuations and nonflow
• Correlated long-range mixed-harmonic fluctuations measured in $pp$, $p$+Pb and low-multiplicity Pb+Pb collisions with the ATLAS detector
• Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems
• Systematic procedure for analyzing cumulants at any order
• Centrality fluctuations in heavy-ion collisions
• A kinetic regime of hydrodynamic fluctuations and long time tails for a Bjorken expansion
• Azimuthal Anisotropy Distributions in High-Energy Collisions
• Cumulants of multiplicity distributions in most-central heavy-ion collisions
• Limitation of multi-particle correlations for studying the event-by-event distribution of harmonic flow in heavy-ion collisions
• Non-flow effects in three-particle mixed-harmonic azimuthal correlations in small collision systems
• The fluctuations of quadrangular flow

Cited by in corpus (30)

• Probing triaxial deformation of atomic nuclei in high-energy heavy ion collisions
• Determination of the neutron skin of ${}^{208}$Pb from ultrarelativistic nuclear collisions
• Evidence of the triaxial structure of ${}^{129}$Xe at the Large Hadron Collider
• Measurement of the azimuthal anisotropy of charged-particle production in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV with the ATLAS detector
• Constraining the quadrupole deformation of atomic nuclei with relativistic nuclear collisions
• Separating the impact of nuclear skin and nuclear deformation in high-energy isobar collisions
• The mean transverse momentum of ultracentral heavy-ion collisions: A new probe of hydrodynamics
• Probing nuclear quadrupole deformation from correlation of elliptic flow and transverse momentum in heavy ion collisions
• Correlations between flow and transverse momentum in Xe+Xe and Pb+Pb collisions at the LHC with the ATLAS detector: a probe of the heavy-ion initial state and nuclear deformation
• Accessing the shape of atomic nuclei with relativistic collisions of isobars
• Higher order Symmetric Cumulants
• Disentangle contributions to small-system collectivity via scans of light nucleus-nucleus collisions
• Possible octupole deformation of ${}^{208}$Pb and the ultracentral $v_2$ to $v_3$ puzzle
• Higher-order transverse momentum fluctuations in heavy-ion collisions
• Disentangling sources of momentum fluctuations in Xe+Xe and Pb+Pb collisions with the ATLAS detector
• Collision-System and Beam-Energy Dependence of Anisotropic Flow Fluctuations
• Measures of azimuthal anisotropy in high-energy collisions
• Bayesian approach to long-range correlations and multiplicity fluctuations in nucleus-nucleus collisions
• Assessing the ultracentral flow puzzle in hydrodynamic modeling of heavy-ion collisions
• Multivariate cumulants in flow analyses: The Next Generation
• Centrality fluctuations and decorrelations in heavy-ion collisions
• Collectivity in large and small systems formed in ultrarelativistic collisions
• Gluonic Hot Spot Initial Conditions in Heavy-Ion Collisions
• Eccentricities, fluctuations and A-dependence of elliptic and triangular flows in heavy-ion collisions
• Multi-particle correlations, cumulants, and moments sensitive to fluctuations in rare-probe azimuthal anisotropy in heavy ion collisions
• Impact parameter dependence of anisotropic flow: Bayesian reconstruction in ultracentral nucleus-nucleus collisions
• Multiplicity fluctuations and correlations in 5.02 TeV p+Pb collisions at zero impact parameter
• Manipulating strong electromagnetic fields with the average transverse momentum of relativistic nuclear collisions
• Turning up and down strong magnetic fields in relativistic nuclear collisions
• Azimuthal anisotropies of charged particles with high transverse momentum in Pb+Pb collisions at $\sqrt{s_{{}_{\text{NN}}}}=5.02$ TeV with the ATLAS detector