Superfluidity in a model of massless fermions coupled to scalar bosons

We study superfluidity in a model of massless fermions coupled to a massive scalar field through a Yukawa interaction. Gap equations for a condensate with total spin J=0 are solved in the mean-field approximation. For the Yukawa interaction, the gaps for right- and left-handed fermions are equal in magnitude and opposite in sign, so that condensation occurs in the J{sup P}=0{sup +} channel. At finite scalar mass, there are two different gaps for fermions of a given chirality, corresponding to condensation of particle pairs or of antiparticle pairs. These gaps become degenerate in the limit of infinite scalar mass. {copyright} {ital 1999} {ital The American Physical Society}