Near-threshold K−d scattering and properties of kaonic deuterium

We calculated the 1s level shifts and widths of kaonic deuterium, corresponding to accurate results on near-threshold antikaon–deuteron scattering. The Lippmann–Schwinger eigenvalue equation with a strong K−–d and Coulomb potentials was solved. The two-body K−–d potentials reproduce the near-threshold elastic amplitudes of K−d scattering obtained from the three-body Alt–Grassberger–Sandhas equations with the coupled channels using two versions of the potentials. The new potentials reproduce the very recent SIDDHARTA data on kaonic hydrogen, experimental data on K−p scattering and have one- or two-pole versions of the Λ(1405) resonance.