Characterizing radial flow fluctuations in relativistic heavy-ion collisions at top RHIC and LHC energies

Abstract

We present a systematic investigation of the transverse-momentum differential radial flow fluctuations observable $v_0(p_T)$ in relativistic heavy-ion collisions at top RHIC ($\sqrt{s_{\mathrm{NN}}}=200$ GeV) and LHC ($\sqrt{s_{\mathrm{NN}}}=2.76$ and 5.02 TeV) energies. Using a multistage hydrodynamic model, we assess the sensitivity of $v_0(p_T)$ to a wide range of physical effects, including bulk and shear viscosities, off-equilibrium corrections at particlization, the presence of a hadronic afterburner, and the nucleon size in the initial conditions. By employing complementary rescaling strategies, we demonstrate how different physical effects leave distinct imprints on the shape of $v_0(p_T)$. A combined double-rescaling of $v_0(p_T)/v_0$ versus $p_T/⟨p_T⟩$ reveals a universality across a wide range of energies and model assumptions in the low-$p_T$ regime, a robust signature of collective behavior. This allows us to disentangle the universal dynamics of the bulk medium from model-specific features that emerge at higher $p_T$. Our results establish $v_0(p_T)$ as a powerful and complementary observable for constraining QGP transport properties and initial-state granularity, offering a unique probe of the created QCD medium.

arXiv comment13 pages, 9 figures; v2: add Appendix B

References in corpus (23)

• Collective flow and viscosity in relativistic heavy-ion collisions
• The equation of state in (2+1)-flavor QCD
• Thermal phenomenology of hadrons from 200 AGeV S+S collisions
• Identified Charged Particle Spectra and Yields in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
• 3+1D hydrodynamic simulation of relativistic heavy-ion collisions
• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• The importance of the bulk viscosity of QCD in ultrarelativistic heavy-ion collisions
• Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions
• The production of photons in relativistic heavy-ion collisions
• Multi-system Bayesian constraints on the transport coefficients of QCD matter
• Higher flow harmonics from (3+1)D event-by-event viscous hydrodynamics
• Spectra and radial flow at RHIC with Tsallis statistics in a Blast-Wave description
• Phenomenological constraints on the transport properties of QCD matter with data-driven model averaging
• Bulk Viscosity Effects in Event-by-Event Relativistic Hydrodynamics
• Interplay of shear and bulk viscosity in generating flow in heavy-ion collisions
• Transverse momentum fluctuations and their correlation with elliptic flow in nuclear collision
• Free-streaming approximation in early dynamics of relativistic heavy-ion collisions
• $p_T$-Dependent Particle Number Fluctuations From Principal Component Analyses in Hydrodynamic Simulations of Heavy-Ion Collisions
• Role of bulk viscosity in deuteron production in ultrarelativistic nuclear collisions
• A Gaussian Process Generative Model for QCD Equation of State
• Multimessenger study of baryon-charged QCD matter in heavy-ion collisions

Cited by in corpus (2)

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• Kinematic and dynamical origins of mean-$p_T$ fluctuations in heavy-ion collisions