Modeling (anti)deuteron formation at RHIC with a geometric coalescence model

TL;DR

This paper presents a wave-function based coalescence model for (anti)deuteron formation in heavy-ion collisions, incorporating spatial emission differences for nucleons and antinucleons to match experimental data across a range of energies.

Contribution

It introduces a novel geometric coalescence model with distinct emission regions for nucleons and antinucleons, accounting for annihilation effects at lower energies.

Findings

Model reproduces experimental coalescence parameters across energies.

Source radii decrease with increasing beam energy.

Antinucleon emission occurs near the fireball surface at lower energies.

Abstract

We study (anti)deuteron formation rates in heavy-ion collisions in the framework of a wave-function based coalescence model. The main feature of our model is that nucleons are emitted from the whole spherically symmetric fireball volume, while antinucleons are emitted only from a spherical shell close to the surface. In this way, the model accounts for nucleon-antinucleon annihilations in the center of the reaction at lower beam energies. Comparison with experimental data on the coalescence parameter in the range $\sqrt{s_{NN}}= 4.7-200$ GeV allows us to extract radii of the respective source geometries. Our results are qualitatively supported by data from the UrQMD transport model which shows a comparable trend in the geometric radii as a function of beam energy. In line with our expectations, we find that at lower energies, the central region of the fireball experiences stronger annihilation than at higher energies.