Cluster production and the chemical freeze-out in expanding hot dense matter

TL;DR

This paper explores how medium effects influence light cluster production during the QCD phase transition, linking Mott transitions to chemical freeze-out and highlighting energy-dependent behaviors in heavy-ion collisions.

Contribution

It introduces a framework connecting Mott transition lines with chemical freeze-out across different energy regimes in heavy-ion collisions.

Findings

At high energies, cluster abundances follow the statistical model.

At low energies, effects like self-energy and Pauli blocking are significant.

Intermediate energies show a correlation between freeze-out and maximum nuclear bound states.

Abstract

We discuss medium effects on light cluster production in the QCD phase diagram by relating Mott transition lines to those for chemical freeze-out. In heavy-ion collisions at highest energies provided by the LHC, light cluster abundances should follow the statistical model because of low baryon densities. Chemical freeze-out in this domain is correlated with the QCD crossover transition. At low energies, in the nuclear fragmentation region, where the freeze-out interferes with the liquid-gas phase transition, self-energy and Pauli blocking effects are important. We demonstrate that at intermediate energies the chemical freeze-out line correlates with the maximum mass fraction of nuclear bound states, in particular $\alpha$ particles. In this domain, the HADES, FAIR and NICA experiments can give new insights.