Flow in AA and pA as an interplay of fluid-like and non-fluid like excitations

Abstract

To study the microscopic structure of quark-gluon plasma, data from hadronic collisions must be confronted with models that go beyond fluid dynamics. Here, we study a simple kinetic theory model that encompasses fluid dynamics but contains also particle-like excitations in a boost invariant setting with no symmetries in the transverse plane and with large initial momentum asymmetries. We determine the relative weight of fluid dynamical and particle like excitations as a function of system size and energy density by comparing kinetic transport to results from the 0th, 1st and 2nd order gradient expansion of viscous fluid dynamics. We then confront this kinetic theory with data on azimuthal flow coefficients over a wide centrality range in PbPb collisions at the LHC, in AuAu collisions at RHIC, and in pPb collisions at the LHC. Evidence is presented that non-hydrodynamic excitations make the dominant contribution to collective flow signals in pPb collisions at the LHC and contribute significantly to flow in peripheral nucleus-nucleus collisions, while fluid-like excitations dominate collectivity in central nucleus-nucleus collisions at collider energies.

28 pages, 16 figures

References in corpus (17)

• Minkowski-space correlators in AdS/CFT correspondence: recipe and applications
• The equation of state in (2+1)-flavor QCD
• The Color Glass Condensate
• Relativistic viscous hydrodynamics, conformal invariance, and holography
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• Search for lepton-universality violation in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Holography and colliding gravitational shock waves in asymptotically AdS_5 spacetime
• 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
• Second order hydrodynamic coefficients from kinetic theory
• The applicability of causal dissipative hydrodynamics to relativistic heavy ion collisions
• Scalings of Elliptic Flow for a Fluid at Finite Shear Viscosity
• Shear viscosity in weakly coupled $\mathcal{N}=4$ Super Yang-Mills theory compared to QCD
• Importance of initial and final state effects for azimuthal correlations in p+Pb collisions
• Elliptic flow in transport theory and hydrodynamics
• SMASH -- A new hadronic transport approach
• Adding new branches to the "Christmas tree" of the quasinormal spectrum of black branes

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