Studies of kaonic atoms and nuclei

Abstract

This contribution reviews recent studies of kaonic atoms and nuclei performed by the Jerusalem-Prague Collaboration using K− optical potentials derived from state-of-the-art chirally-motivated meson-baryon coupled-channel interaction models. Underlying free-space K−N scattering amplitudes are modified to account for in-medium effects caused by Pauli blocking. Strong energy dependence of the amplitudes near threshold is treated self-consistently, which leads to substantial downward subthreshold energy shift. Thorough analyses of kaonic atoms revealed that these K− optical potentials derived within chiral EFT approaches have to be supplemented by a phenomenological term representing K− multi-nucleon interactions in the medium in order to achieve good fits of strong-interaction level shifts and widths in kaonic atoms across the periodic table. It is found that only two of the considered models are simultaneously capable of reproducing the single-nucleon K− absorption fractions at rest from bubble chamber experiments. These models are then applied in optical model calculations of kaonic nuclei. The K− multi-nucleon absorption is found to have a decisive impact on the widths of K−-nuclear quasi-bound states which are excessively large. The detection of kaonic nuclear states is thus most probably limited to the lightest few-body nuclear systems.