PRODUCTION OF STRANGE PARTICLES BY $pi$$sup -$-p INTERACTIONS NEAR THRESHOLD

Observations have been made, in a liquid hydrogen bubble chamber, of the production and decay of strange particles produced by the interaction of 960-Mev pi /sup -/ mesons with protons. The total strange particle production cross section was measured to be 1.02 plus or minus 0.20 millibarns. The cross section is 0.58 plus or minus 0.12 millibarn for LAMBDA /sup 0/-- theta /sup 0/ production, 0.35 plus or minus 0.09 millibarn for SIGMA /sup 0/--K/sup +/ production, and is 0.09 plus or minus 0.04 millibarn for SIGMA /sup -/ -- K/sup +/ particles. Production angular distribution was peaked somewhat backwards for SIGMA /sup 0/ and LAMBDA /sup 0/ hyperons. These cross sections, together with other data, are interpreted as indicating the existence of a very strong interaction for the production of strange particles which extends over a small radius. The decay products uf the LAMBDA /sup 0/ hyperons from LAMBDA /sup 0/-- theta /sup 0/ production were preferentia lly aligned with the incoming beam, a result suggesting a spin of 3/2 for the LAMBDA /sup 0/. Lecay distributions for LAMBDA /sup 0/ particles resulting from SIGMA /sup 0/ decay, and for theta / sup 0/ mesons, were consistent with isotropy.more » (auth)« less