The reaction near threshold
Physik Department T39, Technische Universität München, D-85747 Garching, Germany
Received: 28 October 1998 / Revised version: 12 January 1999 Communicated by F. Lenz
We analyze the recent total cross section data for near threshold measured at COSY. Using an effective range approximation for the on-shell S-wave final state interaction we extract from these data the combination fm4 of the singlet (Ks) and triplet (Kt) threshold transition amplitudes. We present an exploratory calculation of various (tree-level) vector and pseudoscalar meson exchange diagrams. Pointlike -exchange alone and the combined ()-exchange can explain the experimental value of . The pseudoscalar meson exchanges based on a SU(3) chiral Lagrangian turn out to be too large. However, when adding -exchange in combination with the resonant transition and introducing monopole form factors with a cut-off GeV one is again able to reproduce the experimental value of . More exclusive measurements are necessary to reveal the details of the production mechanism.
13.60.Le Meson production - 13.75.Ev Hyperon-nucleon interactions