Multi-antikaonic nuclei in relativistic mean-field theory

Abstract

Properties of multi-antikaonic nuclei (MKN), where several numbers of ${K}^{\ensuremath{-}}$ mesons are bound, are studied in the relativistic mean-field model, combined with chiral dynamics for the kaonic part of the thermodynamic potential. The density profiles for nucleons and ${K}^{\ensuremath{-}}$ mesons, the single particle energy of the ${K}^{\ensuremath{-}}$ mesons, and binding energy of the MKN are obtained. The effects of the $\overline{K}\text{\ensuremath{-}}\overline{K}$ interactions on these quantities are discussed in comparison with other meson ($\ensuremath{\sigma}$, $\ensuremath{\omega}$, and $\ensuremath{\rho}$)-exchange models. It is shown that the $\overline{K}\text{\ensuremath{-}}\overline{K}$ interactions originate from two contributions: One is the contact interaction between antikaons inherent in chiral symmetry, and the other is the one generated through coupling between the ${K}^{\ensuremath{-}}$ and meson mean fields. Both effects of the $\overline{K}\text{\ensuremath{-}}\overline{K}$ repulsive interactions become large on the ground state properties of the MKN as the number of the embedded ${K}^{\ensuremath{-}}$ mesons increases. A relation between the multi-antikaonic nuclei and kaon condensation in infinite and uniform matter is mentioned.