Excitations of SU(5) Monopoles

The author reinterprets Witten's analysis of the dyons in the SU(2) Georgi-Glashow model, showing that his peculiar formula for their electric charge is due to a symmetry of the semiclassical configuration space under the noncompact group of real numbers. This method of analysis extends easily to the SU(5) dyons and shows that their color hypercharge is also arbitrary when the vacuum angle $\theta$ is nonzero.