The paper is devoted to the $\overline{K}NNN$ system, which is an exotic system consisting of an antikaon and three nucleons. Dynamically exact four-body Faddeev-type equations were solved, and characteristics of the quasibound state in the $K^{-}ppn$ system caused by strong interactions were evaluated. Three antikaon-nucleon and three nucleon-nucleon potentials were used, so the dependence of the four-body pole positions on the two-body interaction models was studied. The resulting binding energies $B_{K^{-}ppn}^{\mathrm{Chiral}}\approx 30.5–34.5$ MeV obtained with the chirally motivated and $B_{K^{-}ppn}^{\mathrm{SIDD}}\approx 46.4–52.0$ MeV obtained with the phenomenological antikaon-nucleon potentials are close to those obtained for the $K^{-}pp$ system with the same $\overline{K}N$ and $NN$ potentials, while the four-body widths ${\mathrm{\Gamma }}_{K^{-}ppn}\approx 38.2–50.9$ MeV are smaller.

• Received 29 June 2022
• Accepted 7 October 2022

DOI:https://doi.org/10.1103/PhysRevC.106.064006