Pseudoscalar Goldstone bosons in the color-flavor locked phase at moderate densities

The properties of the pseudoscalar Goldstone bosons in the color-flavor locked phase at moderate densities are studied within a model of the Nambu-Jona-Lasinio type. The Goldstone bosons are constructed explicitly by solving the Bethe-Salpeter equation for quark-quark scattering in random phase approximation. The main focuses of our investigations are (i) the weak decay constant in the chiral limit, (ii) the masses of the flavored (pseudo)Goldstone bosons for nonzero but equal quark masses, (iii) their masses and effective chemical potentials for nonequal quark masses, and (iv) the onset of kaon condensation. We compare our results with the predictions of the low-energy effective field theory. The deviations from results obtained in the weak-coupling limit are discussed in detail.