Global hyperon polarization and effects of decay feeddown

TL;DR

This paper investigates hyperon polarization in heavy-ion collisions, emphasizing decay feeddown effects, and explains polarization ordering observed experimentally, while providing predictions for future data.

Contribution

It introduces a detailed analysis of decay feeddown effects on hyperon polarization and explains the observed polarization hierarchy in heavy-ion collisions.

Findings

Decay feeddown significantly influences measured hyperon polarization.

The polarization ordering $P_{\Omega^-} > P_{\Xi^-} > P_\Lambda$ is naturally explained.

Predictions are made for upcoming RHIC-BES II measurements.

Abstract

We study the global polarizations of $\Lambda$, $\Xi^-$, and $\Omega^-$ hyperons in noncentral Au+Au collisions at $\sqrt{s_\mathrm{NN}}=$ 7.7-200 GeV. We highlight the importance of effect of decay feeddown to the measured global polarization. With the decay contributions taken into account, the global polarization ordering $P_{\Omega^-} > P_{\Xi^-} > P_\Lambda$ can be naturally explained, which is consistent with the observation recently reported from the STAR experiment from Au+Au collisions at 200 GeV. We also extend our calculations to predict expectations from the RHIC-BES II data.