Density determinations in heavy ion collisions

TL;DR

This paper discusses methods to determine freeze-out temperatures and densities in heavy ion collisions, comparing experimental results with models that include medium effects, and proposes a new densitometer based on chemical equilibrium constants.

Contribution

It introduces a quantum statistical model that accounts for medium effects and aligns well with experimental data at high densities, and proposes a novel densitometer for density measurement.

Findings

Medium effects are significant at baryon densities above ~5 x 10^{-4} fm^{-3}.

Quantum statistical model agrees with experimental results at higher densities.

Proposed densitometer based on chemical equilibrium constants.

Abstract

The experimental determination of freeze-out temperatures and densities from the yields of light elements emitted in heavy ion collisions is discussed. Results from different experimental approaches are compared with those of model calculations carried out with and without the inclusion of medium effects. Medium effects become of relevance for baryon densities above $\approx 5 \times 10^{-4}$ fm$^{-3}$. A quantum statistical (QS) model incorporating medium effects is in good agreement with the experimentally derived results at higher densities. A densitometer based on calculated chemical equilibrium constants is proposed.