Enhanced yield ratio of light nuclei in heavy ion collisions with a first-order QCD phase transition

TL;DR

This study uses a transport model with a first-order QCD phase transition to show that density fluctuations during the transition can enhance the yield ratio of light nuclei like tritons relative to protons and deuterons in heavy ion collisions.

Contribution

It demonstrates that the yield ratio of light nuclei is significantly enhanced when the matter's evolution passes through the spinodal region of a first-order chiral phase transition.

Findings

Enhanced yield ratio of $ N_t N_p / N_d^2 $ observed.

Density fluctuations develop during the phase transition.

The enhancement occurs when the trajectory passes through the spinodal region.

Abstract

Using a transport model that includes a first-order chiral phase transition between the partonic and the hadronic matter, we study the development of density fluctuations in the matter produced in heavy ion collisions as it undergoes the phase transition, and their time evolution in later hadronic stage of the collisions. Using the coalescence model to describe the production of deuterons and tritons from nucleons at the kinetic freeze out, we find that the yield ratio $ N_\text{t}N_\text{p}/ N_\text{d}^2$, where $N_\text{p}$, $N_\text{d}$, and $N_\text{t}$ are, respectively, the proton, deuteron, and triton numbers, is enhanced if the evolution trajectory of the produced matter in the QCD phase diagram passes through the spinodal region of a first-order chiral phase transition.