$\Lambda$ and $\bar{\Lambda}$ global polarization from the core-corona model

Abstract

We report on work aimed to describe the $\Lambda$ and $\bar{\Lambda}$ global polarizations in a heavy-ion collision environment using the core-corona model, where the source of these hyperons is a high-density core and a less dense corona. We show that the overall properties of the polarization excitation functions can be linked to the relative abundance of $\Lambda$s and $\bar{\Lambda}$s coming from the core versus those coming from the corona. Both global polarizations peak at collision energies $\sqrt{s_{NN}} \lesssim 10$ GeV. The exact positions and heights of these peaks depend not only on a reversal of relative abundances with collision energy, but also on the centrality class, both related to the QGP volume and lifetime.