# Global $\Lambda$ Polarization in high energy collisions

## TL;DR

This paper uses advanced hydrodynamics simulations with a Yang-Mills flux-tube initial state to analyze the energy dependence and impact parameter effects on global $\\Lambda$ polarization in high energy collisions, matching recent experimental data.

## Contribution

It introduces a novel simulation approach combining Yang-Mills flux-tube initial conditions with (3+1)D PICR hydrodynamics to study $\\Lambda$ polarization across energies.

## Key findings

- Linear impact parameter dependence of polarization.
- Rapid decrease of polarization at low energies.
- Model results align with STAR BES data.

## Abstract

With a Yang-Mills flux-tube initial state and a high resolution (3+1)D Particle-in-Cell Relativistic (PICR) hydrodynamics simulation, we calculate the $\Lambda$ polarization for different energies. The origination of polarization in high energy collisions is discussed, and we find linear impact parameter dependence of the global $\Lambda$ polarization. Furthermore, the global $\Lambda$ polarization in our model decreases very fast in the low energy domain, and the decline curve fits well the recent results of Beam Energy Scan (BES) program launched by the STAR collaboration at the Relativistic Heavy Ion Collider (RHIC). The time evolution of polarization is also discussed.