Spin observables in p̄p→Λ̄Λ with a transverse initial state polarization

The formalism describing the scattering of two spin-12 objects is reviewed for the case of p̄p→Λ̄Λ. It is shown that an experiment utilizing a transverse target polarization can, in principle, completely determine the spin structure of the reaction. Additional measurements, even those using both beam and target polarizations, would not be sensitive to any additional spin dynamics. Thus, the transverse target polarization allows access to the complete set of spin observables, not just the subset upon which the literature has previously focused. This discussion is especially relevant in light of the data collected by PS185/3 at LEAR.