Gauge Kinetic Mixing and Dark Topological Defects

TL;DR

This paper explores how dark sector topological defects, like monopoles and strings, influence the Standard Model via kinetic mixing, revealing phenomena such as induced magnetic fluxes and pseudo monopoles.

Contribution

It introduces a model with gauge symmetry breaking leading to dark monopoles and strings, analyzing their effects on QED magnetic flux through kinetic mixing.

Findings

Dark cosmic strings induce QED magnetic flux via kinetic mixing.

Dark monopoles do not induce QED flux even with kinetic mixing.

Dark bead solutions produce a pseudo magnetic monopole effect.

Abstract

We discuss how the topological defects in the dark sector affect the Standard Model sector when the dark photon has a kinetic mixing with the QED photon. In particular, we consider the dark photon appearing in the successive gauge symmetry breaking, $\mathrm{SU}(2)\to \mathrm{U}(1) \to \mathbb{Z}_2$, where the remaining $\mathbb{Z}_2$ is the center of $\mathrm{SU(2)}$. In this model, the monopole is trapped into the cosmic strings and forms the so-called bead solution. As we will discuss, the dark cosmic string induces the QED magnetic flux inside the dark string through the kinetic mixing. The dark monopole, on the other hand, does not induce the QED magnetic flux in the U(1) symmetric phase, even in the presence of the kinetic mixing. Finally, we show that the dark bead solution induces a spherically symmetric QED magnetic flux through the kinetic mixing. The induced flux looks like the QED magnetic monopole viewed from a distance, although QED satisfies the Bianchi identity everywhere, which we call a pseudo magnetic monopole.