Effects of Virtual Monopoles

TL;DR

This paper explores the theoretical implications and potential empirical signatures of magnetic monopoles and dyons within the Standard Model, highlighting their possible detection through specific particle decay anomalies and collider observables.

Contribution

It introduces the simplest models for adding monopoles and dyons to the Standard Model and analyzes their empirical consequences and current experimental constraints.

Findings

Lower mass limits on monopoles and dyons are stronger than direct search limits.

Anomalies in Z boson decay could indicate monopoles or dyons.

T-odd observables in W pair production are potential signatures, but are constrained by data.

Abstract

Electromagnetism would be a ``more unified'' theory if there were elementary magnetic monopoles and/or particles with both electric and magnetic charges (dyons). I discuss the simplest possibilities for the addition of these entities onto the Standard Model, and their empirical consequences. Lower limits on the masses of monopoles and dyons stemming from their quantum effects on current observables turn out to be much stronger than the existing limits from direct searches. Anomalies in the three-photon decay of the $Z$ constitute good specific signatures for monopoles or dyons. $T$-odd observables in the $e^+e^-\!\rightarrow\! W^+W^-$ process are signatures for dyons, but they are severely constrained by existing data. The subjects of monopolium, monopole cosmology and non-elementary monopoles are also discussed.