Search for magnetic monopoles in polar volcanic rocks

Searches for cosmic magnetic monopoles: past, present and future

A paper titled 'Quantised singularities in the electromagnetic field' by P.A.M. Dirac appeared in 1931 in the Proceedings of the Royal Society A. The paper concerned '[ · s] the reason for the existence of a smallest electric charge.' Dirac showed that the quantization of the electric charge follows from the existence of at least one free magnetic charge, finding 'a connection between the smallest electric charge and the smallest magnetic pole', a connection called since then the 'Dirac relation'. That seminal paper marked the opening of a new research field that has grown considerably since then. The search for magnetic monopoles in cosmic radiation encompasses many fields, from particle physics to astrophysics, from the extremely small to cosmology. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC

MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

Dual and anti-dual modes in dielectric spheres

We present how the angular momentum of light can play an important role to induce a dual or anti-dual behaviour on a dielectric particle. Although the material the particle is made of is not dual, i.e. a dielectric does not interact with an electrical field in the same way as it does with a magnetic one, a spherical particle can behave as a dual system when the correct excitation beam is chosen. We study the conditions under which this dual or anti-dual behaviour can be induced.