Crossing and anti-crossing of energies and widths for the two unbound level system

We calculate and compare the polarization of Λ0 's produced in ultra-relativistic heavy-ion and proton-proton collisions as a signature for the production of Quark Gluon Plasma. Λ0 's produced in heavy-ions come from two different regions characterized by different densities of participants within the interaction zone. In the first one, where the density of participants is larger than a certain critical density, quarks are free and coalesce to produce unpolarized Λ's. In the second zone, where the density is below a certain critical density, Λ's are produced by a recombination mechanism and are therefore polarized. We also discuss possible depolarization effects arising from multiple scattering Λ 's within nuclear matter. (Author)