Hyperon and Kaon-Antikaon Production in Proton-Proton Scattering Close to Threshold at the COSY-11 Facility


In exclusive production of hyperons via the pp->pK+Lambda/Sigma0 channels the Lambda to Sigma0 production ratio at low (Q <= 13 MeV) and equal excess energies is enhanced by an order of magnitude compared to the high energy regime (Q >= 300 MeV). Data on low excess energy Sigma0 production and preliminary results on the energy dependence of the Lambda/Sigma0 ratio are shown and physics implications of the observed suppression are discussed.

In studies of the strangeness dissociation to charged kaon-antikaon pairs via pp->ppK+K- a first total cross section value at an excess energy of 17 MeV, i.e. below the Phi production threshold, is presented.

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Publication: Nucl.Phys. A 691 (2001) 391-394