Unveiling hadronic resonance dynamics at LHC energies: insights from EPOS4

Abstract

International audienceHadronic resonances, with lifetimes of a few fm/\textit{c}, are key tools for studying the hadronic phase in high-energy collisions. This work investigates resonance production in pp collisions at $\sqrt{s} = 13.6$ TeV and in Pb$-$Pb collisions at $\sqrt{s_{\rm{NN}}} = 5.36$ TeV using the EPOS4 model, which can switch the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) ON and OFF, enabling the study of final-state hadronic interactions. We focus on hadronic resonances and the production of non-strange and strange hadrons, addressing effects like rescattering, regeneration, baryon-to-meson production, and strangeness enhancement, using transverse momentum ($p_\textrm{T}$) spectra and particle ratios. Rescattering and strangeness effects are important at low p_\rm{T}, while baryon-to-meson ratios dominate at intermediate p_\rm{T}. A strong mass-dependent radial flow is observed in the most central Pb$-$Pb collisions. The average p_\rm{T}, scaled with reduced hadron mass (mass divided by valence quarks), shows a deviation from linearity for short-lived resonances. By analyzing the yield ratios of short-lived resonances to stable hadrons in pp and Pb$-$Pb collisions, we estimate the time duration ($\tau$) of the hadronic phase as a function of average charged multiplicity. The results show that $\tau$ increases with multiplicity and system size, with a nonzero value in high-multiplicity pp collisions. Proton (p), strange ($\rm{\Lambda}$), and multi-strange ($\rm{\Xi}$, $\rm{\Omega}$) baryon production in central Pb$-$Pb collisions is influenced by strangeness enhancement and baryon-antibaryon annihilation. Comparing with LHC measurements offers insights into the dynamics of the hadronic phase