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

Abstract

We construct the U_L(3) x U_R(3) effective lagrangian which encodes the dynamics of the low energy pseudoscalar excitations in the Color-Flavor-Locking superconducting phase of QCD at finite quark density. We include the effects of instanton-induced interactions and study the mass pattern of the pseudoscalar mesons. A tentative comparison with the analytical estimate for the gap suggests that some of these low energy momentum modes are not stable for moderate values of the quark chemical potential.

Comments: 15 pages, 5 figures; Discussion of quark mass effects at very large densities amended, references added