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.

arXiv comment11 pages, 9 figures, submitted to the New Journal of Physics focus issue "Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to QCD Plasmas"

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Cited by in corpus (24)

• Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV
• Hydrodynamic elliptic and triangular flow in Pb-Pb collisions at sqrt(s)=2.76ATeV
• Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
• Holographic Axion Model: a simple gravitational tool for quantum matter
• On the Temperature Dependence of the Shear Viscosity and Holography
• Bound of diffusion constants from pole-skipping points: spontaneous symmetry breaking and magnetic field
• Universal Bounds on Transport in Holographic Systems with Broken Translations
• Shear viscosity from thermal fluctuations in relativistic conformal fluid dynamics
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• Identifying phase transitions in physical systems with neural networks: a neural architecture search perspective
• The Preferred System of Reference Reloaded