Eur. Phys. J. A (2024) 60: 207
https://doi.org/10.1140/epja/s10050-024-01419-y

Regular Article - Theoretical Physics

Dynamics of identified particles production in oxygen–oxygen collisions at $\sqrt{s_{\text{NN}}}=7$ TeV using EPOS4

¹ University of Science and Technology of China, 230026, Hefei, People’s Republic of China
² Department of Physics and Astronomy, Wayne State University, 666 W. Hancock, 48201, Detroit, Michigan, USA
³ Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, 430079, Wuhan, China
⁴ Pakistan Institute of Nuclear Science and Technology, 44000, Islamabad, Pakistan

^b muashraf@wayne.edu, mashraf@bnl.gov

Received: 5 April 2024
Accepted: 11 September 2024
Published online: 15 October 2024

Abstract

The Large Hadron Collider (LHC) aims to inject oxygen (¹⁶O) ions in the next run into its experiments. This include the anticipated one-day physics run focusing on $O+O$collisions at center-of-mass energy $\sqrt{s_{\text{NN}}}=7$ TeV . In this study, we have used recently developed version of the EPOS (EPOS4) to study the production of identified particles (${\pi }^{\pm }$, $K^{\pm }$ and $p(\overline{p})$) in $O+O$collisions at $\sqrt{s_{\text{NN}}}=7$ TeV . Predictions of transverse momentum ($p_{\text{T}}$) spectra, $⟨p_{\text{T}}⟩$, integrated yield ($\mathrm{d}N/\mathrm{d}\mathit{y}$) for different centrality classes are studied. To provide insight into the collective nature of the produced particles, we look into the $p_{\text{T}}$-differential particle ratios ($K/\pi$ and $p/\pi$) and $p_{\text{T}}$-integrated particle ratios to (${\pi }^{+}+{\pi }^{-}$) as a function of charge particle multiplicity. The shape of the charge particle multiplicity ($\text{d}{N}_{\text{ch}}/\text{d}\eta$) and mean transverse momentum ($⟨p_{\text{T}}⟩$) is well described by EPOS4. The predictions for the ratios of $K/\pi$ and $p/\pi$ from EPOS4 exhibit a systematic overestimation compared to the trends observed in $p+p$, $p+Pb$and $Pb+Pb$systems as a function of charged-particle multiplicity. Interestingly, the $O+O$results of $p_{\text{T}}$-integrated particle ratios shows a clear final state multiplicity overlap with $p+p$, $p+Pb$and $Pb+Pb$collisions. EPOS4 does not only mimics signs of collectivity, but embeds collective expansion by construction, since it relies on relativistic hydrodynamics to model the evolution of the so-called core and is one of the suitable candidates to study ultra-relativistic heavy-ion collisions. Furthermore, the foreseen data from $O+O$collisions at the LHC, when available, will help to better understand the heavy-ion-like behavior in small systems as well as help to put possible constraints on the model parameters.