WK+-nucleus scattering and the "swelling" of nucleons in nuclei

We investigate the utility of the Kmeson as a probe of effective-size modifications ("swelling") of nucleons in the nuclear medium. The K+-nucleus elastic and total cross sections are found to be sensitive to the density-dependent effective masses of the vector mesons whose exchange is responsible for the dominant part of the low-energy K+-nucleon interaction. This density dependence is estimated in several ways and used to construct a K+-nucleus optical potential. Such a model is consistent with the K++C12 data at 800 Mev/c, and provides a physical picture of the "swelling" mechanism in terms of the medium modifications of the meson cloud of the nucleon.