$\Lambda$ polarization in peripheral collisions at moderate relativistic energies

TL;DR

This paper investigates how relativistic effects influence the polarization of $\\Lambda$ hyperons in peripheral heavy ion collisions at energies near the quark-gluon plasma transition, showing that relativistic modifications reduce polarization.

Contribution

It provides the first analysis of $\\Lambda$ polarization at FAIR and NICA energies, highlighting the impact of relativistic effects on polarization from initial shear flow vorticity.

Findings

Relativistic modifications decrease $\\Lambda$ polarization at moderate energies.

Polarization is primarily influenced by initial shear flow vorticity.

Results align with previous higher-energy studies, confirming the effect of relativistic corrections.

Abstract

The polarization of $\Lambda$ hyperons from relativistic flow vorticity is studied in peripheral heavy ion reactions at FAIR and NICA energies, just above the threshold of the transition to the Quark-Gluon Plasma. Previous calculations at higher energies with larger initial angular momentum, predicted significant $\Lambda$ polarization based on the classical vorticity term in the polarization, while relativistic modifications decreased the polarization and changed its structure in the momentum space. At the lower energies studied here, we see the same effect namely that the relativistic modifications decrease the polarization arising from the initial shear flow vorticity.