Short-range repulsion and isospin dependence in the kaon-nucleon [Formula Presented] system

The short-range properties of the kaon-nucleon [Formula Presented] interaction are studied within the meson-exchange model of the Jülich group. Specifically, dynamical explanations for the phenomenological short-range repulsion, required in this model for achieving agreement with the empirical [Formula Presented] data, are explored. Evidence is found that contributions from the exchange of a heavy scalar-isovector meson [Formula Presented] as well as from genuine quark-gluon exchange processes are needed. Taking both mechanisms into account, a satisfactory description of the [Formula Presented] phase shifts can be obtained without resorting to phenomenological pieces. © 2002 The American Physical Society.