Proton Form Factor, Magnetic Charges, and Dyonium

The relativistic quantum dynamics of two particles having both electric and magnetic charges ($e,g$) is discussed. It is shown that this model with its strong long-range forces is a physical realization underlying the dipole magnetic form factor $G_M\mathrm{}\left(t\right)\mathrm{}$ of the proton calculated in the relativistic $O(4,2)\mathrm{}$ model. The mass spectrum gives a linear trajectory for low values of the principal quantum number $N$, contains $N^2$ degeneracy and parity doubling. The slope of the trajectory and the slope of the form factor can be related in principle to the masses of the constituents and the effective electric coupling $\alpha \equiv -(e_1{e}_2+g_1{g}_2)$.