Generalized mesons in dense QCD

QCD superconductors in the color-flavor-locked (CFL) phase support excitati ons (generalized mesons) that can be described as pairs of particles or hol es (rather than particle-hole) around a gapped Fermi surface. In weak coupl ing and to leading logarithm accuracy the scalar and pseudoscalar excitatio ns are massless and the vector and axial-vector excitations are massive and degenerate. The massless scalar excitations are combined with the longitud inal gluons leading to the: Meissner effect in the CFL phase. The mass of t he composite vector excitations is close to twice the gap in weak coupling, hut goes asymptotically to zero with increasing coupling thereby realizing Georgi's vector limit in cold and dense matter. We discuss the possible mi xing of the composite scalar and vector excitations with the gluons, their possible coupling to the modified photons and their decay into light pseudo scalars in the CFL phase. The issue of hidden gauge-symmetry in the QCD sup erconductor is critically examined. The physical implications of our result s on soft dilepton and neutrino emission in cold and dense matter are brief ly discussed. (C) 2000 Elsevier Science B,V. All rights reserved.