Quark-Gluon Plasma at RHIC and the LHC: Perfect Fluid too Perfect?

Abstract

Relativistic heavy ion collisions have reached energies that enable the creation of a novel state of matter termed the quark-gluon plasma. Many observables point to a picture of the medium as rapidly equilibrating and expanding as a nearly inviscid fluid. In this article, we explore the evolution of experimental flow observables as a function of collision energy and attempt to reconcile the observed similarities across a broad energy regime in terms of the initial conditions and viscous hydrodynamics. If the initial spatial anisotropies are very similar for all collision energies from 39 GeV to 2.76 TeV, we find that viscous hydrodynamics might be consistent with the level of agreement for v2 of unidentified hadrons as a function of pT . However, we predict a strong collision energy dependence for the proton v2(pT). The results presented in this paper highlight the need for more systematic studies and a re-evaluation of previously stated sensitivities to the early time dynamics and properties of the medium.

11 pages, 9 figures, submitted to the New Journal of Physics focus issue "Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to QCD Plasmas"

References in corpus (12)

• Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
• Viscosity, Black Holes, and Quantum Field Theory
• Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions
• The centrality dependence of elliptic flow, the hydrodynamic limit, and the viscosity of hot QCD
• Elliptic flow in the Gaussian model of eccentricity fluctuations
• Effect of flow fluctuations and nonflow on elliptic flow methods
• The eccentricity in heavy-ion collisions from Color Glass Condensate initial conditions
• On the necessity to include event-by-event fluctuations in experimental evaluation of elliptical flow
• The applicability of causal dissipative hydrodynamics to relativistic heavy ion collisions
• Quantitative Constraints on the Transport Properties of Hot Partonic Matter from Semi-Inclusive Single High Transverse Momentum Pion Suppression in Au+Au collisions at sqrt(s_NN) = 200 GeV
• Hydrodynamic radial and elliptic flow in heavy-ion collisions from AGS to LHC energies
• Suppression of the shear viscosity near the critical temperature in hot QCD

Cited by in corpus (15)

• Holographic Axion Model: a simple gravitational tool for quantum matter
• Bound of diffusion constants from pole-skipping points: spontaneous symmetry breaking and magnetic field
• Universal Bounds on Transport in Holographic Systems with Broken Translations
• On the universality of AdS${}_2$ diffusion bounds and the breakdown of linearized hydrodynamics
• DREENA-A framework as a QGP tomography tool
• Shear flows in far-from-equilibrium strongly coupled fluids
• Upper bound of the charge diffusion constant in holography
• Impact of fragment formation on shear viscosity in the nuclear liquid-gas phase transition region
• Constraining $\eta /s$ through high-p${}_{\perp }$ theory and data
• Early evolution constrained by high-$p_T$ QGP tomography
• $\eta (T)/s(T)$ and collective flow in chiral hydrodynamics
• Production of thermal photons in viscous fluid dynamics with temperature-dependent shear viscosity
• Identifying phase transitions in physical systems with neural networks: a neural architecture search perspective
• Shear viscoelasticity in anisotropic holographic axion model
• The Preferred System of Reference Reloaded