Speaker
Description
Identified charged-hadron production ($\pi^{\pm}$, $K^{\pm}$, and $p(\bar{p})$) in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV is investigated within the EPOS4 framework to study the role of late-stage hadronic interactions. Simulations are performed both with and without the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) hadronic afterburner, enabling a quantitative assessment of hadronic phase effects. Key observables, including charged-particle multiplicity ($dN_{\mathrm{ch}}/d\eta$), transverse momentum ($p_{\mathrm{T}}$) spectra, and both $p_{\mathrm{T}}$-differential and integrated particle ratios ($K/\pi$ and $p/\pi$), are analyzed. The results indicate that the low-$p_{\mathrm{T}}$ region is strongly influenced by hadronic rescattering and strangeness enhancement, reflected in a centrality-dependent increase of the $K/\pi$ ratio. At intermediate $p_{\mathrm{T}}$, an enhanced baryon-to-meson ratio ($p/\pi$) is observed, consistent with the effects of radial flow and quark recombination. The inclusion of UrQMD leads to improved agreement with ALICE measurements, particularly in reproducing the spectral shapes and mass-dependent collective behavior. Hadronic processes such as baryon--antibaryon annihilation and resonance decays significantly modify the final particle distributions, highlighting the importance of the hadronic phase. Overall, EPOS4 coupled with UrQMD provides a consistent description of the centrality and mass dependence of charged-particle production, emphasizing the essential role of late-stage hadronic dynamics in shaping final-state observables.