SUBTHRESHOLD K+ PRODUCTION ON NUCLEI BY PI(+) MESONS

The inclusive K+ mesons production in pi(+)-nucleus reactions in the s ubthreshold energy regime is analyzed with respect to the one-step (pi (+) n --> K+ Lambda) and the two-step (pi(+) n --> eta p(1), eta p(2) --> K+ Lambda) incoherent production processes on the basis of an appr opriate folding model, which allows one to take into account the vario us forms of an internal nucleon momentum distribution as well as on- a nd off-shell propagation of the struck target nucleon. Contrary to pro ton-nucleus reactions primary reaction channel is found to be signific ant practically at all considered energies. Detailed predictions for t he K+ total and invariant differential cross sections from pi(+)C(12)- and pi(+) Pb-208-collisions subthreshold energies are provided.