Measurement Of The (P)Over-Bar-P->(Lambda)Over-Bar-Lambda And (P)Over-Bar-P->(Sigma)Over-Bar(0)Lambda+Cc Reactions At 1.726 And 1.771 Gev/C

Interest in the production of hyperon-antihyperon pairs following antiproton-proton annihilation stems largely from attempts to understand the nature of flavor production. To date the major focus of both the experimental and the theoretical effort has been on the (p) over bar p--><(Lambda)over bar>Lambda reaction. In this paper, we present data on the complementary channels (p) over bar p--><(Sigma)over bar>(0) Lambda and (p) over bar p--><(Lambda)over bar>Sigma(0). Events from the kinematically similar (p) over bar p--><(Lambda)over bar>Lambda reaction were obtained in parallel. The procedure to distinguish these three separate reactions is described and results for all channels are presented. These include the total and differential cross sections, hyperon polarizations, and spin correlation coefficients. Data were obtained at incident antiproton lab momenta of 1.726 and 1.771 GeV/c which correspond to excess kinetic energies in the (p) over bar p--><(Lambda)over bar>Sigma(0)+c.c. reaction of 26 and 40 MeV, respectively, above threshold. Comparisons are made to earlier work at similar excess energies in the (p) over bar p--><(Lambda)over bar>Lambda channel. The low-energy regime has been highlighted in this experiment to reduce the complexity in the theoretical analysis.