Elliptic flow at energies available at the CERN Large Hadron Collider: Comparing heavy-ion data to viscous hydrodynamic predictions

Abstract

I compare the first viscous hydrodynamic prediction for integrated elliptic flow in Pb-Pb collisions at the LHC with the first data released by the ALICE collaboration. These new data are found to be consistent with hydrodynamic extrapolations of RHIC data with no change in medium parameters (e.g., average viscosity). I also discuss how, in general, a precise comparison of data to theoretical calculations requires an understanding of some subtleties of the measurement -- most notably the cut on transverse momentum of the particles used and the differing sensitivities to flow fluctuations and non-flow effects of the various measurement methods.

3 pages, 3 figures; v2: added plots of charged hadron multiplicity and identified particle differential elliptic flow, and a few minor changes

References in corpus (15)

• Conformal Relativistic Viscous Hydrodynamics: Applications to RHIC results at sqrt(s_NN) = 200 GeV
• Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Elliptic flow from two- and four-particle correlations in Au + Au collisions at sqrt{s_{NN}} = 130 GeV
• Charged-particle multiplicity density at mid-rapidity in central Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Effect of flow fluctuations and nonflow on elliptic flow methods
• Viscous Hydrodynamic Predictions for Nuclear Collisions at the LHC
• Eccentricity fluctuations and elliptic flow at RHIC
• Non-flow correlations and elliptic flow fluctuations in gold-gold collisions at sqrt(s_NN)= 200 GeV
• Elliptic flow in U+U collisions at sqrt{s_{NN}} = 200 GeV and in Pb+Pb collisions at sqrt{s_{NN}} = 2.76 TeV: Prediction from a hybrid approach
• Hydrodynamic radial and elliptic flow in heavy-ion collisions from AGS to LHC energies
• Soft heavy-ion physics from hydrodynamics with statistical hadronization - predictions for the Large Hadron Collider
• Elliptic flow in nuclear collisions at the Large Hadron Collider
• Hydrodynamic predictions for Pb+Pb collisions at 2.76 TeV
• Multiplicity, mean $p_T$, $p_T$-spectra and elliptic flow of identified particles in Pb+Pb collisions at LHC

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• Hydrodynamic elliptic and triangular flow in Pb-Pb collisions at sqrt(s)=2.76ATeV
• Measurement with the ATLAS detector of multi-particle azimuthal correlations in p+Pb collisions at sqrt(s_NN)=5.02 TeV
• Particle spectra in Pb-Pb collisions at 2.76 TeV
• The stickiness of sound: An absolute lower limit on viscosity and the breakdown of second order relativistic hydrodynamics
• The Shear Viscosity to Entropy Ratio: A Status Report
• Elliptic flow in 200 A GeV Au+Au collisions and 2.76 A TeV Pb+Pb collisions: insights from viscous hydrodynamics + hadron cascade hybrid model
• Integrated Dynamical Approach to Relativistic Heavy Ion Collisions
• Relativistic hydrodynamics in heavy-ion collisions: general aspects and recent developments
• Collision Energy Dependence of Viscous Hydrodynamic Flow in Relativistic Heavy-Ion Collisions
• Constraining models of initial conditions with elliptic and triangular flow data
• Towards the Little Bang Standard Model
• Relativistic Fluid Dynamics In and Out of Equilibrium -- Ten Years of Progress in Theory and Numerical Simulations of Nuclear Collisions
• Elliptic flow in Pb+Pb collisions at sqrt{s_{NN}} = 2.76 TeV: hybrid model assessment of the first data
• Second order viscous corrections to the harmonic spectrum in heavy ion collisions
• New relativistic dissipative fluid dynamics from kinetic theory
• Identified Particle Spectra and Anisotropic Flow in an Event-by-Event Hybrid Approach in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV
• Dynamics of QCD Matter -- current status
• New paradigm for fluctuations in heavy-ion collisions
• Flow in heavy-ion collisions - Theory Perspective
• Collective phenomena in ultra-relativistic nuclear collisions: anisotropic flow and more
• Elliptic flow of charged pions, protons and strange particles emitted in Pb+Au collisions at top SPS energy
• Resonance Decay Contributions to Higher-Order Anisotropic Flow Coefficients
• Viscosity, non-conformal equation of state and sound velocity in Landau hydrodynamics
• Elliptic and Hexadecapole flow of charged hadron in viscous hydrodynamics with Glauber and Color Glass Condensate initial conditions for Pb-Pb collision at $\sqrt{s_{NN}}$=2.76 TeV
• Gluonic Hot Spot Initial Conditions in Heavy-Ion Collisions
• Spectra, flow and HBT in Pb-Pb collisions at the LHC
• Dependence of elliptic flow on transverse momentum in 200 GeV Au-Au and 2.76 TeV Pb-Pb collisions
• Hadron momentum spectra from analytical solutions of relativistic hydrodynamics
• Formulation of relativistic dissipative fluid dynamics and its applications in heavy-ion collisions
• On the Perturbative Evaluation of Thermal Green's Functions in the Bulk and Shear Channels of Yang-Mills Theory