Neutral Magnetic Monopole in the Standard Model

Abstract

The standard model has the electroweak monopole which has the magnetic charge $4\pi/e$, as a hybrid between the Dirac and 'tHooft-Polyakov monopoles. We argue that it may have new type of monopoles, in particular the neutral monopole (``the Z monopole") which is electromagnetically neutral but has the neutral magnetic charge $4\pi/\be$, where $\be$ is the neutral charge. The mass of the new monopole could be less than the Cho-Maison monopole, around 3.28 TeV. We show how to construct the neutral monopole and clarify the origin of the topology of the new monopole. We discuss the implications of the new monopoles in physics.