Exact fermion-dyon scattering solutions

We analyze the Dirac equation for an $I=\frac{1}{2}$ fermion in the field of an SU(2) Julia-Zee dyon. In the Prasad-Sommerfield limit we obtain exact $J=0\mathrm{}$ partial-wave solutions for massless fermions. These solutions describe charge-exchange scattering as well as dyon decay via charged-fermion-pair emission. When the initial fermion-dyon Coulomb interaction is repulsive, low-momentum single-particle $J=0\mathrm{}$ scattering is prohibited. Implications of our results for proton decay catalysis by SU(5) dyons are briefly discussed.