Scattering of fermions from a cosmic string

The Dirac equation is solved for a fermion in the background field of a cosmic string. We focus on the amplitude of the spinor at the core radius and study its dependence on the flux along the string and on the core model used. Our results show that there is an amplification of the wave function at the core radius for some values of the flux. The implications for baryon decay catalyzed by cosmic strings are discussed. We show that, for certain values of the string flux, the catalysis cross section is a strong interaction cross section. The elastic and inelastic scattering cross sections are calculated and the model dependence of the results discussed. (orig.)