HIGH-RESOLUTION STUDY OF HYPERON-NUCLEON INTERACTIONS BY ASSOCIATED STRANGENESS PRODUCTION IN PP COLLISIONS

The associated strangeness production in pp collisions was studied at bombarding energies of 2.3 and 2.7 GeV by detecting the outgoing K+ particles with a high resolution magnetic spectrometer at forward angles up to 23.5-degrees laboratory angle. The kaons were separated from an immense background of protons and pions by a highly resolving TOF electronics in addition to vetoes from Cerenkov detectors utilizing either beta differing Cerenkov light cones in lucite or different thresholds for light production in aerogel. The hyperon-nucleon missing mass spectra obtained show strong deviations from pure phase space which is ascribed to final state interations of the pLAMBDA and the NSIGMA systems. The structures found are discussed and compared with results from K-d --> pi-YN experiments, with theoretical calculations in the frame of OBE models, and with the prediction of sharp strange dibaryon resonances from several quark-bag models.