Color superconductor with a color-sextet condensate

We analyze color superconductivity of one massive flavor quark matter at moderate baryon density with a spin-zero color-sextet condensate. The most general Higgs-type ground-state expectation value of the order parameter implies complete breakdown of the SU(3)xU(1) symmetry. However, both the conventional fourth-order polynomial effective bosonic description, and the NJL-type fermionic description in the mean-field approximation favor an enhanced SO(3) symmetry of the ground state. We ascribe this finding to the failure of the mean-field approximation and propose that a more sophisticated technique is needed.