We have studied the structure of K^- pp comprehensively by solving this three-body system in a variational method, starting from the Ansatz that the Λ (1405) resonance (≡ Λ^*) is a K^- p bound state. The structure of K^- pp reveals a molecular feature, namely, the K^- in Λ^* as an "atomic center" plays a key role in producing strong covalent bonding with the other proton. We point out that strongly bound Kbar nuclear systems are formed by "super strong" nuclear force due to migrating real bosonic particles Kbar a la Heitler-London-Heisenberg, whereas the normal nuclear force is caused by mediating virtual mesons. We have shown that the elementary process, p + p → K⁺ + Λ^* + p, which occurs in a short impact parameter and with a large momentum transfer, leads to unusually large self-trapping of Λ^* by the involved proton, since the Λ^*-p system exists as a compact doorway state propagating to K^-pp.

(Contributed by Toshimitsu YAMAZAKI, M.J.A.)