  Effective nuclear densities probed by kaon- and anti-kaon-nucleus systems are
studied theoretically both for bound and low energy scattering states. As for
the anti-kaon bound states, we investigate kaonic atoms. We find that the
effective density depends on the atomic states significantly and we have the
possibility to obtain the anti-kaon properties at various nuclear densities by
observing the several kaonic atom states. We also find the energy dependence of
the probed density by kaon and anti-kaon scattering states. We find that the
study of the effective nuclear density will help to find the proper systems to
investigate the meson properties at various nuclear densities.
