Strings, monopoles, and meson states

Dirac's formulation of the monopole theory modified by an additional mass term for the gauge field has been considered as a possible simplified model for quark binding. Methods are discussed for the consistent regularization of the infinities present in the resulting action and equations of motion. This leads to an action which is the same as that suggested by previous authors. It is shown that the expression for the energy of the modified action still has infinities unless the mass of the gauge field is infinite. Thus the regularization procedure is incomplete when the gauge field has finite mass. Applications of the regularized model to charmonium and other meson states are discussed. (U.S.)