Energy Dependence of Light Nuclei ($d$, $t$) Production at STAR

TL;DR

This study investigates how light nuclei production varies with collision energy in heavy-ion experiments, aiming to understand phase transition signals and the QCD critical point through yield ratios and coalescence parameters.

Contribution

It provides the first detailed measurement of light nuclei production and related observables across a wide energy range in Au+Au collisions at RHIC.

Findings

Energy dependence observed in coalescence parameters $B_2$ and $B_3$

Variation in particle yield ratios ($d/p$, $t/p$, $t/d$) with energy

Implications for QCD phase transition and critical point signals

Abstract

In high-energy nuclear collisions, the production of light nuclei is sensitive to the temperature and phase-space density of the system at freeze-out. In addition, the phase transition from QGP to the hadronic phase will lead to large baryon density fluctuation, which will be reflected in the light nuclei production. For example, the ratio of proton ($N(p)$) and triton ($N(t)$) to deuteron ($N(d)$) yields, which is defined as $N(t)$$\cdot$$N(p)$/$N^2(d)$, may be used as a sensitive observable to search for the QCD critical point. In this paper, we will report the energy dependence of light nuclei ($d$, $t$) production in Au+Au collisions at $\sqrt{s_{NN}}$ =7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV measured by the STAR experiment at RHIC. We will present the beam energy dependence for the coalescence parameter $B_2(d)$ and $B_3(t)$, particle ratios ($d/p$, $t/p$, and $t/d$), and the yield ratio of $N(t)$$\cdot$$N(p)$/$N^2(d)$. Their physics implications will be discussed.