The Quest for Pionic and Kaonic Nuclear Bound Systems Following Yukawa and Tomonaga

Abstract

After sketching some historical events related to Yukawa and Tomonaga concerning the birth of mesons, the author describes recent developments in the spectroscopy of pion-nucleus bound states via "pion-transfer" reactions. The role of pions as Nambu-Goldstone bosons in nuclear media is emphasized by recently obtained experimental evidence for the partial restoration of chiral symmetry breaking. New light is shed on K mesons, which play a unique role in forming dense nuclear systems. The basic unit, K − pp, is predicted to possess a molecular structure with quasi-Λ(1405) as an "atomic constituent". We find here super strong nuclear force produced by a migrating real K meson in the Heitler-London-Heisenberg scheme in place of the normal nuclear force mediated by Yukawa's virtual mesons.

Isotopes and Analogs of Hydrogen – from Fundamental Investigations to Practical Applications

“…In the era when the nucleus was believed to contain electrons, unsuccessful attempts were made to understand nuclear structure in terms of the exchange of "real" electrons between the protons in the nucleus; these were abandoned in favor of the modern picture which paints the interaction in terms of the exchange of "virtual" bosons, a picture that developed from Yukawa's original idea that the strong force required a massive exchange particle. The kpp cluster has been proposed by Yamazaki as exhibiting a "super strong nuclear force" in which a real kaon participates in a molecule-like Heitler-London exchange interaction 167 .…”

Extending the Topological Analysis and Seeking the Real-Space Subsystems in Non-Coulombic Systems with Homogeneous Potential Energy Functions

“…[17] On the other hand, in recent decades a wealth of experimental and theoretical evidence has been accumulated demonstrating molecular-like structure for systems not traditionally considered as molecular systems. One may include in this list the "nuclear molecules" in nuclear physics, [18,19] various "exotic molecules" composed of fundamental particles other than electrons, protons and neutrons, [20][21][22][23][24][25][26][27][28][29][30][31] "artificial molecules" in condensed-matter physics, [32][33][34][35] and the "molecular Bose-Einstein condensates". [36][37][38][39] In considering such molecular-like systems the question emerges whether any underlying AIM structure is derivable from the wavefunctions of these systems.…”