Magnetic catalysis in the presence of scalar fields

The influence of scalar field interactions in the magnetic catalysis phenomenon is studied in a gauge theory with scalar and fermion fields. It is shown that the external magnetic field catalyzes the appearance of a fermion-antifermion condensate along with a non-zero scalar vev, hence generating a fermion dynamical mass and breaking the discrete chiral symmetry of the theory. 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 does it exhibit dimensional transmutation a la Coleman-Weinberg. The scalar vev noticeably enhances the dynamically generated fermion mass. Possible cosmological applications of these results are suggested. (C) 2000 Elsevier Science B.V. All rights reserved.