The rho meson in a nuclear medium
  In this work, propagation properties of the rho meson in symmetric nuclear matter are studied. We make use of a coupled channel unitary approach to meson-meson scattering, calculated from the lowest order Chiral Perturbation Theory lagrangian including explicit resonance fields. Low energy chiral constraints are considered by matching our expressions to those of one loop Ch.P.T. To account for the medium corrections, the rho couples to pion-pion and kaon-antikaon pairs which are properly renormalized in the nuclear medium. 
D. Cabrera, E. Oset, M. J. Vicente Vacas