  We have studied the structure of K- pp nuclear cluster comprehensively by
solving this three-body system exactly in a variational method starting from
the Ansatz that the Lambda(1405) resonance (Lambda*) is a K-p bound state. We
have found that our original prediction for the presence of K-pp as a compact
bound system with M = 2322$ MeV/c2, B = 48 MeV and Gamma = 60 MeV remains
unchanged by varying the Kba-rN and NN interactions widely as far as they
reproduce Lambda(1405). The structure of K- pp reveals a molecular feature,
namely, the K- in Lambda* as an "atomic center" plays a key role in producing
strong covalent bonding with the other proton. We have shown that the
elementary process, p + p -> K+ + Lambda* + p, which occurs in a short impact
parameter and with a large momentum transfer (Q ~ 1.6$ GeV/c), leads to
unusually large self-trapping of Lambda* by the participating proton, since the
Lambda*-p system exists as a compact doorway state propagating to K- pp
(R{Lambda*-p} ~ 1.67 fm).
