Three-body calculation of the $1s$ level shift in kaonic deuterium with realistic $\bar{K}N$ potentials

Abstract

The $1s$ level shift in kaonic deuterium was calculated using Coulomb Sturmian expansion of Faddeev equations. The convergence of the method yields an $\sim\ 1\ eV$ accuracy for the level shifts. We used three different, realistic, multichannel $\bar{K}N$ interactions reproducing all known experimental two-body $\bar{K}N$ data. The different results suggest, that the level shift should be in the range $\Delta E\sim(800\pm30)-(480\pm20){\rm i}\ \ eV$. The (almost) exact level shifts were compared with values, given by the commonly used approximations.