Chemical Equilibrium in Collisions of Small Systems

TL;DR

This paper investigates how particle production, especially strange particles, depends on system size in heavy-ion collisions using statistical models, comparing suppression mechanisms and analyzing data from various collision systems.

Contribution

It provides a systematic comparison of two strangeness suppression models and analyzes their system-size dependence using experimental data at SPS energies.

Findings

Strangeness correlation radius shows weak dependence on system size.

No clear difference between the two suppression mechanisms based on the data.

System-size dependence of thermal parameters is characterized.

Abstract

The system-size dependence of particle production in heavy-ion collisions at the top SPS energy is analyzed in terms of the statistical model. A systematic comparison is made of two suppression mechanisms that quantify strange particle yields in ultra-relativistic heavy-ion collisions: the canonical model with strangeness correlation radius determined from the data and the model formulated in the canonical ensemble using chemical off-equilibrium strangeness suppression factor. The system-size dependence of the correlation radius and the thermal parameters are obtained for p-p, C-C, Si-Si and Pb-Pb collisions at sqrt(s_NN) = 17.3 AGeV. It is shown that on the basis of a consistent set of data there is no clear difference between the two suppression patterns. In the present study the strangeness correlation radius was found to exhibit a rather weak dependence on the system size.