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

Lipei Du

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Phys. Rev. C 113, 014901 – Published 6 January, 2026

DOI: https://doi.org/10.1103/9pvq-ph1c

Abstract

This study presents a systematic investigation of the transverse-momentum differential radial flow fluctuations observable v0(pT) in relativistic heavy-ion collisions at top Relativistic Heavy Ion Collider (sNN=200 GeV) and Large Hadron Collider (sNN=2.76 and 5.02 TeV) energies. Using a multistage hydrodynamic model, this study assesses the sensitivity of v0(pT) 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, this study demonstrates how different physical effects leave distinct imprints on the shape of v0(pT). A combined double-rescaling of v0(pT)/v0 versus pT/〈pT〉 reveals a universality across a wide range of energies and model assumptions in the low-pT 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 pT. These results establish v0(pT) as a powerful and complementary observable for constraining quark-gluon plasma transport properties and initial-state granularity, offering a unique probe of the created QCD medium.

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Phys. Rev. C 113, 014901– Published 6 January, 2026
  • Received 22 August 2025
  • Accepted 16 December 2025
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