Strangeness Production at the SPS

TL;DR

This paper reports on systematic measurements of strange hyperons and phi mesons at SPS energies, highlighting discrepancies with hadronic transport models and supporting statistical models, with new data on short-lived resonances indicating rescattering effects.

Contribution

It provides new experimental data on strangeness production at SPS energies and compares different theoretical models, emphasizing the limitations of transport models and the success of statistical approaches.

Findings

Transport models fail to describe multi-strange particle production.

Statistical models agree well with measured yields.

Resonance yields are suppressed due to rescattering.

Abstract

Systematic studies on the production of strange hyperons and the phi meson as a function of beam energy and system size performed by the NA49 collaboration are discussed. Hadronic transport models fail to describe the production of multi strange particles (Xi, Omega), while statistical models are generally in good agreement to the measured particle yields at all energies. The system size dependence is well reproduced by the core-corona approach. New data on K*(892) production are presented. The yields of these short-lived resonances are significantly below the statistical model expectation. This is in line with the interpretation that the measurable yields are reduced due to rescattering of their decay products inside the fireball.