Transverse-momentum spectra of strange particles produced in Pb+Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV in the chemical non-equilibrium model

TL;DR

This study models the transverse-momentum spectra of strange particles in Pb+Pb collisions at 2.76 TeV using a chemical non-equilibrium framework within the Cracow model, successfully describing most measured particle spectra and their centrality dependence.

Contribution

It introduces a combined chemical non-equilibrium and single-freeze-out approach within the Cracow model to describe strange particle spectra at LHC energies, extending previous multiplicity ratio analyses.

Findings

Excellent fit to proton and meson spectra.

Satisfactory description of hyperon spectra.

Potential for improved hyperon modeling with internal emission assumptions.

Abstract

We analyze the transverse-momentum spectra of strange hadrons produced in Pb+Pb collisions at the collision energy $\sqrt{s_{\rm NN}}=2.76$ TeV. Our approach combines the concept of chemical non-equilibrium with the single-freeze-out scenario. The two ideas are realized in the framework of the Cracow model, whose thermodynamic parameters have been established in earlier studies of the ratios of hadron multiplicities. The geometric parameters of the model are obtained from the fit to the spectra of pions and kaons, only. Using these parameters, we obtain an excellent description of the spectra of protons and the $K_S^0$, $K^*(892)^0$, and $\phi(1020)$ mesons. A satisfactory description is also obtained for the $\Lambda$, $\Xi$ and $\Omega$ hyperons. Further improvement of the hyperon spectra may be achieved if we assume that they are emitted from a smaller, internal part of the system but at the same thermodynamic conditions. Our work not only includes all particle species measured up to now in heavy-ion collisions at the LHC energies but, in addition, discusses the centrality dependence of the particle production.