K+ PRODUCTION IN PROTON AND DEUTERON INDUCED REACTIONS AT SUBTHRESHOLD ENERGIES

The production of K+ mesons in proton-nucleus and deuteron-nucleus collisions is analyzed with respect to one-step nucleon-nucleon (NN --> NLAMBDAK+), DELTA-nucleon (DELTAN --> NLAMBDAK+) and two-step pion-nucleon (piN --> K+ LAMBDA) production channels on the basis of experimental ground state momentum distributions and free on-shell production processes. Whereas for K+ production in proton-nucleus reactions the secondary channel piN clearly dominates at subthreshold energies, meson and nucleon induced channels are of similar magnitude in deuteron-nucleus reactions. Contrary to nucleus-nucleus collisions the DELTA induced reaction channels are found to be of minor importance. The experimental differentiation of the underlying microscopic reaction channels appears possible via differential proton - K+ coincidence measurements as shown in detail by the microscopic simulations including proton rescattering.