One- versus two-pole $\bar{K}N - \pi \Sigma$ potential: $K^- d$ scattering length

We investigated the dependence of the $K^- d$ scattering length on models of $\bar{K}N$ interaction with one or two poles for $\Lambda(1405)$ resonance. The $\bar{K}NN - \pi \Sigma N$ system is described by coupled-channel Faddeev equations in AGS form. Our new two-body $\bar{K}N - \pi \Sigma$ potentials reproduce all existing experimental data on $K^- p$ scattering and kaonic hydrogen atom characteristics. New models of $\Sigma N - \Lambda N$ interaction were also constructed. Comparison with several approximations, usually used for scattering length calculations, was performed.