Three-body approach to theK−dscattering length in particle basis

We report on the first calculation of the scattering length ${A}_{{K}^{\ensuremath{-}}d}$ based on a relativistic three-body approach where the $\overline{K}N$ coupled channel two-body input amplitudes have been obtained with the chiral $\mathrm{SU}(3)$ constraint, but with isospin symmetry breaking effects taken into account. Results are compared with a recent calculation applying a similar set of two-body amplitudes, based on the fixed center approximation, and for which we find significant deviations from the three-body results. Effects of the deuteron D-wave component, pion-nucleon, and hyperon-nucleon interactions are also evaluated.