K¯D¯N molecular state as a “ uudsc¯ pentaquark” in a three-body calculation

Abstract

We predict a new three-body hadronic molecule composed of antikaon $\overline{K}$, anticharm meson $\overline{D}$, and nucleon $N$ with spin-parity ${J}^{P}=1/{2}^{+}$ and isospin $I=1/2$. This state behaves like an explicit pentaquark state because its minimal quark configuration is $uuds\overline{c}$ or $udds\overline{c}$. Owing to the attraction between every pair of two hadrons, in particular the $\overline{K}\overline{D}$ attraction which dynamically generates ${D}_{s0}{(2317)}^{\ensuremath{-}}$ and $\overline{K}N$ attraction which dynamically generates $\mathrm{\ensuremath{\Lambda}}(1405)$, the $\overline{K}\overline{D}N$ system is bound, and the real (imaginary) part of its eigenenergy is calculated as $3253\phantom{\rule{4.pt}{0ex}}\text{MeV}$ (minus a few MeV) in a nonrelativistic three-body potential model. We discuss properties of this $\overline{K}\overline{D}N$ quasibound state which emerge uniquely in three-body dynamics.