EPJ Featured Talk: First direct measurement of radial flow in heavy-ion collisions with ALICE

Abstract

This work presents measurements of the transverse-momentum-dependent observable $v_0(p_{\mathrm{T}})$ as a novel probe of radial expansion dynamics in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ALICE detector. Results are reported for inclusive charged hadrons, pions, kaons, and protons across centrality intervals, using a pseudorapidity gap to suppress short-range nonflow correlations. At low $p_{\mathrm{T}}$, a clear mass ordering is observed, consistent with hydrodynamic expectations. For $p_{\mathrm{T}}>3$ GeV/$c$, protons exhibit larger $v_0(p_{\mathrm{T}})$ than pions and kaons, in line with quark recombination models. These results demonstrate the sensitivity of $v_0(p_{\mathrm{T}})$ to collective expansion and hadronization dynamics in the quark--gluon plasma.

arXiv comment5 pages, 2 figures; contribution to the XXXI International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2025)

References in corpus (10)

• Microscopic Models for Ultrarelativistic Heavy Ion Collisions
• Thermal phenomenology of hadrons from 200 AGeV S+S collisions
• Fluctuating Glasma initial conditions and flow in heavy ion collisions
• Hadron production in heavy ion collisions: Fragmentation and recombination from a dense parton phase
• 3+1D hydrodynamic simulation of relativistic heavy-ion collisions
• Performance of the ALICE VZERO system
• Production of charged pions, kaons and (anti-)protons in Pb-Pb and inelastic pp collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• Anisotropic flow of charged particles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Relativistic hydrodynamics for heavy-ion collisions
• Transverse momentum fluctuations and their correlation with elliptic flow in nuclear collision