Kaon-antikaon nuclear optical potentials and the kappa meson in the   nuclear medium
  We study the properties of the kappa meson in the nuclear medium, starting from a chiral unitary model of S-wave, I=1/2 K-pi scattering, which describes the elastic K-pi phase shifts and generates a pole in the amplitude. Medium effects are considered by including pion and kaon selfenergies. We explore the changes in the kappa pole position and in the K-pi scattering amplitude at finite density, with two different models for the kaon selfenergy. 
D. Cabrera and M. J. Vicente Vacas