Spin transfer in $\bar{p}p\rightarrow\bar{\Lambda}\Lambda$

A complete determination of spin observables for $\bar{p}p\rightarrow\bar{\Lambda}\Lambda$, at an antiproton lab momentum of 1.637 GeV/c, has been made by the PS185 Collaboration. The results of this experiment disagree strongly with the predictions of calculations which used either meson-exchange or quark models for the reaction mechanism. The experiment will be repeated at FAIR by the PANDA Collaboration, and extended to higher energies. A model-independent description of the spin structure of this reaction is provided by the transition matrix $M$, which can be written in the center of mass frame as a function of 6 complex parameters. These parameters are also determined by any model calculation for $\bar{p}p\rightarrow\bar{\Lambda}\Lambda$, so they are related to the reaction mechanism and initial and final state interactions. We have computed these parameters for several reaction mechanisms, and have explored their dependence on initial and final state interactions.