On two-color QCD with baryon chemical potential

We study SU(2) color QCD with even number of quark flavors. First, using QC D inequalities we show that at finite baryon chemical potential mu, condens ation must occur in the channel with scalar diquark quantum numbers. This b reaks the U(1) symmetry generated by baryon charge (baryon superconductivit y). Then we derive the effective Lagrangian describing low lying meson and baryon excitations using extended local chiral symmetry of the theory, This enables us to determine the leading term in the dependence of the masses o n mu exactly. (C) 1999 Elsevier Science B.V. All rights reserved.