Massive quark effects in two flavor color superconductors

Abstract

The high density effective theory formalism (HDET) is employed to describe high density QCD with two massive flavors (2SC). The gap equation is derived and explicitly solved for the gap parameter. The parameters associated to the pseudo Nambu-Goldstone boson of $U(1)_A$ are evaluated in the limit $\mu\to\infty$ and $m/\mu$ fixed. In particular we find for the velocity of the NG boson the relation $v^2=\sqrt{\mu_1^2-m_1^2}\sqrt{\mu_2^2-m_2^2}/3\mu_1\mu_2$.Comment: Latex file. 14 pages, 2 figures. Some improvement in the presentation. 2 references added. Final version to be published in Physics Letter