Minicharges and Magnetic Monopoles

TL;DR

The paper addresses whether minicharged particles arising from kinetic mixing between two U(1) gauge factors can coexist with magnetic monopoles. It analyzes angular-momentum quantization to derive the allowed monopole charges, identifying two monopole types that avoid inconsistencies for any mixing parameter $\chi$. It then shows that in a model where one U(1) emerges from an SU(2) broken to U(1), the 't Hooft-Polyakov monopoles realize these allowed types and remain unaffected by kinetic mixing. The result establishes compatibility between minicharged particles and monopoles, suggesting that experimental searches for hidden U(1) sectors can leverage monopole considerations and non-Abelian origins to probe new physics.

Abstract

Minicharged particles arise naturally in extensions of the Standard Model with a kinetic mixing term between the ordinary electromagnetic U(1) and an extra "hidden sector" U(1). In this note we study the compatibility of these particles with the existence of magnetic monopoles. We find that angular momentum quantization allows only certain combinations of ordinary and hidden monopole charge. Using the example where one of the U(1)s originates from a spontaneously broken SU(2), we demonstrate that exactly the allowed types of monopoles arise as 't Hooft-Polyakov monopoles.

Figures (1)

• Figure 1: Feynman diagram for a contribution of a particle charged under both gauge groups to the kinetic mixing.