Ju n 20 01 Non - localities and Fermi motion corrections in K − atoms

We evaluate the p–wave K − N amplitudes from the chiral Lagrangians and from there construct the p–wave part of the K − nucleus optical potential plus a small s–wave part induced from the elementary p–wave amplitude and the nuclear Fermi motion. Simultaneously, the momentum and energy dependence of the s–wave optical potential, previously developed, are taken into account and shown to generate a small p–wave correction to the optical potential. All the corrections considered are small compared to the leading s–wave potential, and lead to changes in the shifts and widths which are smaller than the experimental errors. A thorough study of the threshold region and low densities is conducted, revealing mathematical problems for which a physical solution is given.