Strong interaction effects in kaonic atoms (and nuclear matter distribution shape)

Strong interaction effects in kaonic atoms manifest themselves in energy shifts, line width broadenings and intensity reductions of the last observable transitions. They depend on the basic interaction between a K/sup -/ and a nucleon and on the nuclear matter distribution at the surface of the nucleus. With a low momentum K/sup -/ beam at the CERN PS, X-ray measurements have been performed in the low and medium Z region. The measured energies and line widths are compared with calculated ones which were obtained by solving the Klein-Gordon equation for an extended nucleus in the presence of an optical potential describing the strong K/sup -/-nucleus interaction. It seems that the data can only be explained by assuming an attractive K/sup -/-nucleus interaction. This fact sheds some light on the connection between the parameters of the optical potential and the K /sup -/-nucleon scattering lengths which are repulsive at threshold energy. The dependence of the measurable quantities on the nuclear matter distribution is discussed. The sensitivity becomes larger with increasing Z number. (1 refs).