Masses of the Goldstone modes in the CFL phase of QCD at finite density

We construct the U-l(3) X U-R(3) effective lagrangian which encodes the dyn amics of the low energy pseudoscalar excitations in the Color-Flavor-Lockin g superconducting phase of QCD at finite quark density. We include the effe cts of instanton-induced interactions and study the mass pattern of the pse udoscalar masons. A tentative comparison with the analytical estimate for t he gap suggests that some of these low energy momentum modes are not stable for moderate values of the quark chemical potential mu. (C) 2000 Elsevier Science B.V. All rights reserved.