Experimental determination of the complete spin structure for p̅ p→Λ̅ Λ at p_p̅ =1.637 GeV/c

The reaction p̅ p→Λ̅ Λ→p̅ π⁺pπ^- has been measured with high statistics at a beam momentum of p_p̅ =1.637GeV/c. The use of a transversely polarized frozen-spin target combined with the self-analyzing property of Λ/Λ̅ decay allows access to unprecedented information on the spin structure of the interaction. The most general spin-scattering matrix can be written in terms of 11 real parameters for each bin of scattering angle; each of these parameters is determined with reasonable precision. From these results, all conceivable spin correlations are determined with inherent self-consistency. Good agreement is found with the few previously existing measurements of spin observables in p̅ p→Λ̅ Λ near this energy. Existing theoretical models do not give good predictions for those spin observables that had not been previously measured.