Possible S-wave Bound-States of Two Pseudoscalar Mesons

Using the potentials derived from vector-meson-exchanges, the $K\bar{K}$, $DK$, $B\bar{K}$, $D\bar{D}$, $B\bar{B}$, $BD$, $\bar{D}K$, $BK$ and $B\bar{D}$ systems are studied. Possible S-wave bound-states of two pseudoscalar mesons are discussed. We find that systems of $DB$, $D\bar{D}$, $B\bar{B}$ and $DK$ with isospin 0 are likely to form S-wave bound states via strong interactions while the others are unlikely to be bound by the strong interaction sector alone. With the Coulomb potential, the $K^{+}{K}^{-}$ system can form an atomic bound state

• the kaonium. The influence of the one-meson-exchange potential on the ground state energy of the kaonium and its decay widths to $\pi \pi$ and $\pi \eta$ are evaluated.