Testing the quark-exchange contribution to the nuclear force inK−p atoms

The strong annihilation of $K^{\mathrm{-}}$p atoms to Λπ and Σπ proceeds not only through intermediate resonance formation [primarily the Λ(1405)], but also, due to the composite structure of the hadrons involved, by means of quark rearrangements induced by residual quark-quark interactions. We evaluate the amplitudes for these rearrangement processes using a QCD-like potential model and show them to be of the correct sign and magnitude, relative to the reasonably well-known resonance contributions, to explain the experimentally observed $K^{\mathrm{-}}$p branching fractions. This result, in addition to being relevant to the interpretation of the Λ(1405), provides an independent check of the quark-exchange mechanisms believed responsible for short-distance nucleon-nucleon interactions.