Kaonic Nuclear Clusters --- a New Paradigm of Particle and Nuclear Physics ---

Abstract: Lambda*=Lambda(1405) plays an essential role in forming kaonic nuclear clusters (KNC). The simplest KNC, K-pp, has the structure Lambda*p=(K-p){I=0}p, where a real kaon migrates between two nucleons, mediating super-strong Lambda*-p$ attraction. Production data of K-pp have been accumulated by DISTO, J-PARC E27 and J-PARC E15 experiments. In the case of K-K-pp, the attractive covalent bond of Lambda*Lambda* is doubly enhanced compared to the Lambda*-p one. As a consequence, a m-th Lambda* multiplet, (Lambda*)m, with m(m-1)/2 bonds becomes more stable than its corresponding neutron aggregate, (n)m, with m=8 ~ 12. This may suggest the possible existence of stable Lambda* matter. The production of K-K-pp by high-energy pp or heavy-ion collisions is awaited as a doorway to so-far unknown Lambda* matter.