Model for topological fermions

We introduce a model designed to describe charged particles as stable topol ogical solitons of a field with values on the internal space S-3. These sol itons behave like particles with relativistic properties like Lorentz contr action and velocity dependence of mass. This mass is defined by the energy of the soliton. In this sense this model is a generalization of the Sine-Go rdon model(1) from 1+1-dimensions to 3+1-dimensions, from S-1 to S-3. For l arge distances from the centre of solitons this model tends to a dual U(1)- theory with freely propagating electromagnetic waves. Already at the classi cal level it describes important effects, which usually have to be explaine d by quantum field theory, like particle-antiparticle annihilation and the running of the coupling.