Coupled-channels three-body calculations of an $I=1/2,J^{\pi }=0^{-}$ $\overline{K}\mathit{NN}$ quasibound state in the $\overline{K}\mathit{NN}\text{−}\pi \Sigma N$ system were performed and the dependence of the resulting three-body energy on the two-body $\overline{K}N\text{−}\pi \Sigma$ interaction was investigated. Earlier results of binding energy $B_{K^{-}\mathit{pp}}~50\text{−}70$ MeV and width ${\Gamma }_{K^{-}\mathit{pp}}~100$ MeV are confirmed [N. V. Shevchenko et al., Phys. Rev. Lett. 98, 082301 (2007)]. It is shown that a suitably constructed energy-independent complex $\overline{K}N$ potential gives a considerably shallower and narrower three-body quasibound state than the full coupled-channels calculation. Comparison with other calculations is made.

• Received 2 July 2007

DOI:https://doi.org/10.1103/PhysRevC.76.044004