Kaonic atoms and in-medium $K^{-}N$ amplitudes

Abstract

Recent work on the connection between in-medium subthreshold $K^{-}N$ amplitudes and kaonic atom potentials is updated by using a next to leading order chirally motivated coupled channel separable interaction model that reproduces $\bar{K}N$ observables at low energies, including the very recent SIDDHARTA results for the atomic $K^{-}$-hydrogen $1s$ level shift and width. The corresponding $K^{-}$-nucleus potential is evaluated self-consistently within a single-nucleon approach and is critically reviewed with respect to empirical features of phenomenological optical potentials. The need to supplement the single-nucleon based approach with multi-nucleon interactions is demonstrated by showing that additional empirical absorptive and dispersive terms, beyond the reach of chirally motivated $K^{-}$-nucleus potentials, are required in order to achieve good agreement with the bulk of the data on kaonic atoms.

Comments: V3 updating references to match the published version