Singularities of Magnetic Monopoles for Dirac and 't Hooft-Polyakov Theories by Pre-potential Method

The magnetic monopole is one of the important problems in the early stage of universe as well as observations and experiments on Earth. We study the existence or non-existence of the Dirac and the 't Hooft-Polyakov magnetic monopole theories using the pre-potential $\boldsymbol{C}$, which is defined to derive the vector potential by the curl operation as $\boldsymbol{A}=\nabla \times \boldsymbol{C}$ . We assert that the magnetic singularity exists for the 't Hooft-Polyakov monopole in SO(3) gauge theory, as well as for the Dirac monopole in U(1) gauge theory. The regularization method confirms our assertion.