Core meets corona: A two-component source to explain Λ and Λ‾ global polarization in semi-central heavy-ion collisions

Abstract

We compute the Λ and Λ‾ global polarization in semi-central heavy-ion collisions modeling the source as consisting of a high-density core and a less dense corona. We show that when more Λs than Λ‾s are produced in the corona, and this is combined with a smaller number of Λs coming from the core, as compared to those coming from the corona, an amplification effect for the Λ‾ with respect to that of Λ polarization can occur. This amplification becomes more important for lower collision energies and quantitatively accounts for the Λ and Λ‾ polarizations measured by the STAR beam energy scan.