K-Nucleus Optical Potential

A nonlocal, energy-dependent, $K^{-}$-nucleus optical potential is derived by means of the independent pair approximation and a $t$-matrix method. Strong coupling of the $K^{-}$-proton pair to the ${Y_0}^{*}$ is taken into account. The effects of nonlocality and off-energy-shell behavior of the $t$ matrix are found to be appreciable. Approximately equivalent local potentials are defined; they all differ significantly from the shape of the nuclear density in the surface region. Shifts and widths of levels in several light kaonic atoms are calculated and found to be in reasonable agreement with experiment.