Effective K̅ N interaction based on chiral SU(3) dynamics

The effective K̅ N interaction based on chiral SU(3) coupled-channel dynamics is derived and its extrapolation below the K̅ N threshold is studied in detail. Starting from the coupled-channel scattering equations, we eliminate the channels other than K̅ N and obtain an effective interaction in the single K̅ N channel. An equivalent local potential in coordinate space is constructed such as to reproduce the full scattering amplitude of the chiral SU(3) coupled-channel framework. We discuss several realistic chiral SU(3)-based models in comparison to reach conclusions about the uncertainties involved. It turns out that, in the region relevant to the discussion of deeply bound K̅ -nuclear few-body systems, the resulting energy-dependent, equivalent local potential is substantially less attractive than the one suggested in previous purely phenomenological treatments.