Global spin polarization of multistrange hyperons and feed-down effect in heavy-ion collisions.

Global spin polarization of hyperons is an important observable to probe the vorticity of the quark-gluon plasma produced in heavy-ion collisions. We calculate the global polarizations of Λ, Ξ − , and Ω − in Au+Au collisions at energies s NN = 7.7–200 GeV based on a multiphase transport model. Our calculations suggest that their primary global polarizations fulfill P Ω − ≃ 5 / 3 P Ξ − ≃ 5 / 3 P Λ. We also estimate the feed-down effect of particle decay on the global polarization. With the feed-down effect taken into account, the global polarizations of Λ and Ξ − are clearly separated, and the final global polarizations are in the ordering: P Ω − > P Ξ − > P Λ. Such a relation can be tested in experiments, which will provide us more information about the global polarization mechanism. [ABSTRACT FROM AUTHOR]