Magnetic catalysis in the presence of scalar fields

The influence of scalar field interactions in the magnetic catalysis phenom enon is studied in a gauge theory with scalar and fermion fields. It is sho wn that the external magnetic field catalyzes the appearance of a fermion-a ntifermion condensate along with a non-zero scalar vev, hence generating a fermion dynamical mass and breaking the discrete chiral symmetry of the the ory. The model does not require the introduction of a scalar mass term with a wrong sign in the original Lagrangian to generate the scalar vev, nor do es it exhibit dimensional transmutation "a la Coleman-Weinberg." The scalar vev noticeably enhances the dynamically generated fermion mass. Possible c osmological applications of these results are suggested. (C) 2000 Elsevier Science B.V. All rights reserved.