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Production of hyperons and antihyperons in the interactions of 6.935 BeV/c antiprotons with protons has been studied. A total of 80 000 pictures taken with the Brookhaven National Laboratory 80-in. liquidhydrogen bubble chamber have been analyzed for all possible final states involving the production of a hyperon and/or an antihyperon. The total cross section for events in this category is 1.3±0.1 mb. Reactions leading to two-, three-, or four-body final states involving A or 2 hyperons (or their antiparticles) were produced highly peripherally. The angular distribution of the AA final state can be fitted to K* (888) exchange when the absorptive effect of competing channels is taken into account. Ratios among cross sections of various hyperon-antihyperon pair states agree with predictions from SUz symmetry, assuming a dominant K or K* exchange and an F-type coupling. Charge ratios of events with S ± and Fi** (1385) are also consistent with single-particle-exchange models. We have examined the mass spectra of all possible mass combinations of all possible final states. The Fi* (1385) was by far the most prominent resonance produced, and production of F 0 * (1405) and F 0 * (1520) was also observed. Although the energy available in the production center-of-mass system is 3.86 BeV, there was no statistically significant evidence for the production of any new meson or baryon resonance. A thorough search has been made for Or and 0 + particles, but no event was found to be consistent with their production and decay.

A high speed computer program for the kinematical analysis of bubble chamber events is described. The program treats individual particle interaction or decay vertices, subjecting the measured variables to the equations of energy and momentum according to the least-squares criterion. This is done in four different cases in which the problem is overdetermined, and a fifth case is calculated in which the problem is just determined. The adjusted or computed variables corresponding to each particle are obtained in all cases as well as the first-order error matrices for each type of variable. A connected chain of vertices may be processed in sequence.

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Diffraction dissociation of both the beam and target particles has been observed in 150-GeV/c .ir--p interactions in the Fermilab 30-in.-bubble-chamber--proportional-wirechambe hybrid spectrometer. The dissociations are observed as recoil systems opposite leading particles, the signals of which are separated from background where appropriate by a variant of the Van Hove sector cut, thus allowing the high-mass portion of the spectrum to be observed. Pion dissociation has a cross section of 1758-t. 105 pb, divided among two-, four., and six-prong events; some p0 production is seen and comes primarily from the n--t2n-.ir + channel. The proton dissociation cross section is 1726, 100 pb, again divided among two-, four-, and six-prong events. The final state contains a neutron more frequently than a proton in the twoand six-prong events, a proton more frequently in the four-prong events. Production of A + + is observed in the p +p.irf T -dissociations. transferring four-momenhim to other particles,