Λ⁰ polarization as a probe for production of deconfined matter in ultrarelativistic heavy-ion collisions

We study the polarization change of Λ⁰’s produced in ultrarelativistic heavy-ion collisions with respect to the polarization observed in proton-proton collisions as a signal for the formation of a quark-gluon plasma (QGP). Assuming that, when the density of participants in the collision is larger than the critical density for QGP formation, the Λ⁰ production mechanism changes from recombination type processes to the coalescence of free valence quarks, we find that the Λ⁰ polarization depends on the relative contribution of each process to the total number of Λ⁰’s produced in the collision. To describe the polarization of Λ⁰’s in nuclear collisions for densities below the critical density for the QGP formation, we use the DeGrand-Miettinen model corrected for the effects introduced by multiple scattering of the produced Λ⁰ within the nuclear environment.