Search For Monopoles Research Articles

Direct detection of primordial black hole relics as dark matter

If dark matter is composed of primordial black holes, such black holes can span an enormous range of masses. A variety of observational constraints exist on massive black holes, and black holes with masses below 1015 g are often assumed to have completely evaporated by the present day. But if the evaporation process halts at the Planck scale, it would leave behind a stable relic, and such objects could constitute the entirety of dark matter. Neutral Planck-scale relics are effectively invisible to both astrophysical and direct detection searches. However, we argue that such relics may typically carry electric charge, making them visible to terrestrial detectors. We evaluate constraints and detection prospects in detail, and show that if not already ruled out by monopole searches, this scenario can be largely explored within the next decade using existing or planned experimental equipment. A single detection would have enormous implications for cosmology, black hole physics, and quantum gravity.

Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production.

MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

All roads lead to the Dirac quantization condition

The existence of magnetic monopoles is a sufficient argument to explain the quantization of electric charge, an argument that was presented by Dirac. Regardless of the status of any search for magnetic monopoles, the formal description of the quantum mechanics of a charged particle in the field of a magnetic monopole is very rich and has increased our understanding of the mathematical structures underlying this description, as well as of its physical implications. In this short review, we present four different arguments all leading to the Dirac quantization condition, emphasizing their geometrical and topological aspects.

Monopole production via photon fusion and Drell\u2013Yan processes: MadGraph implementation and perturbativity via velocity-dependent coupling and magnetic moment as novel features

In this work we consider point-like monopole production via photon-fusion and Drell–Yan processes in the framework of an effective U(1) gauge field theory obtained from conventional models describing the interaction of spin magnetically-charged fields with ordinary photons, upon electric-magnetic dualisation. We present arguments based on such dualities which support the conjecture of an effective monopole-velocity-dependent magnetic charge. For the cases of spin- and spin-1 monopoles, we also include a magnetic-moment term kappa , which is treated as a new phenomenological parameter and, together with the velocity-dependent coupling, allows for a perturbative treatment of the cross-section calculation. We discuss unitarity issues within these effective field theories, in particular we point out that in the spin-1 monopole case only the value kappa =1 may restore unitarity. However from an effective-field-theory point of view, this lack of unitarity should not be viewed as an impediment for the phenomenological studies and experimental searches of generic spin-1 monopoles, given that the potential appearance of new degrees of freedom in the ultraviolet completion of such models might restore it. The second part of the paper deals with an appropriate implementation of photon-fusion and Drell–Yan processes based on the above theoretical scenarios into MadGraph UFO models, aimed to serve as a useful tool in interpretations of monopole searches at colliders such as LHC, especially for photon fusion, given that it has not been considered by experimental collaborations so far. Moreover, the experimental implications of such perturbatively reliable monopole searches have been laid out.

Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb−1 of 13 TeV proton–proton collisions at the LHC

We update our previous search for trapped magnetic monopoles in LHC Run 2 using nearly six times more integrated luminosity and including additional models for the interpretation of the data. The MoEDAL forward trapping detector, comprising 222 kg of aluminium samples, was exposed to 2.11 fb−1 of 13 TeV proton–proton collisions near the LHCb interaction point and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to the Dirac charge or above are excluded in all samples. The results are interpreted in Drell–Yan production models for monopoles with spins 0, 1/2 and 1: in addition to standard point-like couplings, we also consider couplings with momentum-dependent form factors. The search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

Proposal for the detection of magnetic monopoles in spin ice via nanoscale magnetometry

We present a proposal for applying nanoscale magnetometry to the search for magnetic monopoles in the spin ice materials holmium and dysprosium titanate. Employing Monte Carlo simulations of the dipolar spin ice model, we find that when cooled to below $1.5\,$K these materials exhibit a sufficiently low monopole density to enable the direct observation of magnetic fields from individual monopoles. At these temperatures we demonstrate that noise spectroscopy can capture the intrinsic fluctuations associated with monopole dynamics, allowing one to isolate the qualitative effects associated with both the Coulomb interaction between monopoles and the topological constraints implied by Dirac strings. We describe in detail three different nanoscale magnetometry platforms (muon spin rotation, nitrogen vacancy defects, and nanoSQUID arrays) that can be used to detect monopoles in these experiments, and analyze the advantages of each.

Magnetic monopoles and a cheap detector

The letters from Ken Frankel and Christopher Harrison (Physics Today, June 2017, page 13) in response to Arttu Rajantie’s article on the history of searches for magnetic monopoles (Physics Today, October 2016, page 40) brought back a memory. After Blas Cabrera’s 1982 publication of a candidate monopole event detected with a superconducting loop,11. B. Cabrera, Phys. Rev. Lett. 48, 1378 (1982). https://doi.org/10.1103/PhysRevLett.48.1378 three groups22. J. Incandela et al., Phys. Rev. Lett. 53, 2067 (1984); https://doi.org/10.1103/PhysRevLett.53.2067S. Bermon et al., Phys. Rev. Lett. 55, 1850 (1985); https://doi.org/10.1103/PhysRevLett.55.1850A. D. Caplin et al., Nature 317, 234 (1985); https://doi.org/10.1038/317234a0S. Somalwar et al., Nucl. Instrum. Methods Phys. Res. A 226, 341 (1984). https://doi.org/10.1016/0168-9002(84)90046-9—a University of Chicago, Fermilab, and University of Michigan collaboration; IBM; and Imperial College London—built Faraday induction detectors with larger areas. Using a coincidence technique of two gradiometer detectors in a nonzero but pinned magnetic field, Joe Incandela and coworkers showed that a likely explanation of the candidate event was a flux jump rather than the transit of a monopole.33. J. Incandela et al., Phys. Rev. D 34, 2637 (1986); https://doi.org/10.1103/PhysRevD.34.2637J. R. Incandela, “A search for magnetic monopoles using superconducting induction detectors,” PhD thesis, U. Chicago (1986). I was invited by the organizers of the First Aspen Winter Conference to give a review talk of the hot though cryogenic topic.44. H. J. Frisch, Ann. NY Acad. Sci. 461, 652 (1986). https://doi.org/10.1111/j.1749-6632.1986.tb52444.xI had been a graduate student at the University of California, Berkeley, and had great admiration for Luis Alvarez, so I sent him a draft asking for comments. I had leaned over backwards to give him credit for inventing the Faraday induction technique, as my looking in depth at monopole detection by ionization brought home that there was no way to calibrate the ionization detector, and hence a nondetection could never be definitive. Faraday detection, however, can be calibrated with a “pseudopole,” a very long but small-diameter, tightly wound, magnetic solenoid much akin to a Dirac string.I was working at my desk when my phone rang, with a furious Luis on the other end. Without any introduction, he barked, “Henry, this was my idea, and I should be the first reference.” I was stunned, as I thought I had done him proud, but I managed to say, “Luis, the guys ahead of you are not to be sneezed at—Faraday, Maxwell, Dirac… .” Still angry, he said, “Yes, but who are these other guys?” Luis later sent a nice note praising the review, and all was well.A brief addendum: Sunil Somalwar’s PhD thesis followed up on Incandela’s superconducting gradiometers by showing that using just copper wire and a field-effect transistor operating at liquid nitrogen temperature, one could build an inexpensive detector, capable of covering large areas and sensitive to a single Dirac charge.55. S. Somalwar, H. Frisch, J. Incandela, Phys. Rev. D 37, 2403 (1988). https://doi.org/10.1103/PhysRevD.37.2403ReferencesSection:ChooseTop of pageReferences <<1. B. Cabrera, Phys. Rev. Lett. 48, 1378 (1982). https://doi.org/10.1103/PhysRevLett.48.1378, Google ScholarCrossref2. J. Incandela et al., Phys. Rev. Lett. 53, 2067 (1984); https://doi.org/10.1103/PhysRevLett.53.2067, Google ScholarCrossrefS. Bermon et al., Phys. Rev. Lett. 55, 1850 (1985); https://doi.org/10.1103/PhysRevLett.55.1850, , Google ScholarCrossrefA. D. Caplin et al., Nature 317, 234 (1985); https://doi.org/10.1038/317234a0, , Google ScholarCrossrefS. Somalwar et al., Nucl. Instrum. Methods Phys. Res. A 226, 341 (1984). https://doi.org/10.1016/0168-9002(84)90046-9, , Google ScholarCrossref3. J. Incandela et al., Phys. Rev. D 34, 2637 (1986); https://doi.org/10.1103/PhysRevD.34.2637, Google ScholarCrossrefJ. R. Incandela, “A search for magnetic monopoles using superconducting induction detectors,” PhD thesis, U. Chicago (1986). , Google Scholar4. H. J. Frisch, Ann. NY Acad. Sci. 461, 652 (1986). https://doi.org/10.1111/j.1749-6632.1986.tb52444.x, Google ScholarCrossref5. S. Somalwar, H. Frisch, J. Incandela, Phys. Rev. D 37, 2403 (1988). https://doi.org/10.1103/PhysRevD.37.2403, Google ScholarCrossref© 2018 American Institute of Physics.

Gauss&amp;#39;s Law for Magnetism &amp;amp; Law of Universal Magnetism: Calculate the Charge of a Monopole

This paper describes a mathematical proof that Gauss’s Law for Magnetism can be derived from the Law of Universal Magnetism [1]. A second reciprocal proof also shows that the Law of Universal Magnetism can be derived from Gauss’s Law for Magnetism. These two complimentary proofs confirm that the Law of Universal Magnetism is a valid equation rooted in Gaussian law. The paper also confirms the theoretical existence of the magnetic monopole and calculates its magnetic charge using the ratio of the electromagnetic field and the speed of light. Using the mass-to-charge ratio of an electron, the mass and radius of the magnetic monopole are determined. The monopole is found to have the same radius as the electron and can also be found in the electromagnetic spectrum range known as gamma rays. Lightning is a natural source of gamma rays and could prove fruitful in the search for monopoles.

Searches for magnetic monopoles with IceCube

Particles that carry a magnetic monopole charge are proposed by various theories which go beyond the Standard Model of particle physics. The expected mass of magnetic monopoles varies depending on the theory describing its origin, generally the monopole mass far exceeds those which can be created at accelerators. Magnetic monopoles gain kinetic energy in large scale galactic magnetic fields and, depending on their mass, can obtain relativistic velocities. IceCube is a high energy neutrino detector using the clear ice at the South Pole as a detection medium. As monopoles pass through this ice they produce optical light by a variety of mechanisms. With increasing velocity, they produce light by catalysis of baryon decay, luminescence in the ice associated with electronic excitations, indirect and direct Cherenkov light from the monopole track, and Cherenkov light from cascades induced by pair creation and photonuclear reactions. By searching for this light, current best limits for the monopole flux over a broad range of velocities was achieved using the IceCube detector. A review of these magnetic monopole searches is presented.

Search for magnetic monopoles with the MoEDAL forward trapping detector in 13 TeV proton-proton collisions at the LHC

The MoEDAL experiment addresses a decades-old issue, the search for an elementary magnetic monopole, first theorised in 1931 by Dirac to explain electric charge quantisation. Since then it was showed that magnetic monopoles occur naturally in grand unified theories as solutions of classical equations of motion. The dedicated experiment can enjoy a new energy regime opened at the LHC allowing direct probes of magnetic monopoles at the TeV scale for the first time. MoEDAL pioneered a technique in which monopoles would be slowed down in a dedicated aluminium array and the presence of trapped monopoles is probed by analysing the samples with a superconducting magnetometer. The MoEDAL forward trapping detector array deployed in 2015 was analysed and found consistent with zero trapped magnetic charge, allowing to set the first LHC constraints for monopoles carrying twice or thrice the Dirac charge.

Searches for magnetic monopoles and beyond with MoEDAL at the LHC

The MoEDAL experiment at the LHC is optimised to detect highly-ionising particles such as magnetic monopoles, dyons and (multiply) electrically-charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the LHCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes, while cavern backgrounds are being monitored with an array of MediPix detectors. The detector concept and its physics reach is presented with emphasis given to recent results on monopole searches providing the best limits on high magnetic charges in colliders. The potential to search for heavy, long-lived supersymmetric electrically-charged particles and multi-charged states is also discussed.

Ongoing magnetic monopole searches with IceCube

The IceCube collaboration has instrumented a cubic kilometer of ice with 5160 photo-multipliers. While mainly developed to detect Cherenkov light, any visible light can be used to detect particles within the ice. Magnetic monopoles are hypothetical particles predicted by many theories that extend the Standard model of Particle Physics. They are carriers of a single elementary magnetic charge. For this particle, different light production mechanisms dominate from direct Cherenkov light at highly relativistic velocities (&gt; 0:76 c), indirect Cherenkov light at mildly relativistic velocities (&gt; 0:5 c to 0:76 c), luminescence light at low relativistic velocities (≳ 0:1 c to 0:5 c), as well as catalysis of proton decay at non relativistic velocities (≲ 0:1 c). For each of this speed ranges, searches for magnetic monopoles at the IceCube experiment are either in progress or they have already set the worlds best limits on the flux of magnetic monopoles. A summary of these searches will be presented, outlining already existing results as well as methods used by the currently conducted searches.

Search for relativistic magnetic monopoles with five years of the ANTARES detector data

A search for magnetic monopoles using five years of data recorded with the ANTARES neutrino telescope from January 2008 to December 2012 with a total live time of 1121 days is presented. The analysis is carried out in the range β > 0.6 of magnetic monopole velocities using a strategy based on run-by-run Monte Carlo simulations. No signal above the background expectation from atmospheric muons and atmospheric neutrinos is observed, and upper limits are set on the magnetic monopole flux ranging from 5.7 × 10−16 to 1.5 × 10−18 cm−2·s−1·sr−1.

The MoEDAL experiment at the LHC: status and results

The MoEDAL experiment at the LHC is optimised to detect highly ionising particles such as magnetic monopoles, dyons and (multiply) electrically charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the LHCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes (MMTs), while spallation-product backgrounds are being monitored with an array of MediPix pixel detectors. An introduction to the detector concept and its physics reach, complementary to that of the large general purpose LHC experiments ATLAS and CMS, will be given. Emphasis is given to the recent MoEDAL results at 13 TeV, where the null results from a search for magnetic monopoles in MMTs exposed in 2015 LHC collisions set the world-best limits on particles with magnetic charges more than 1.5 Dirac charge. The potential to search for heavy, long-lived supersymmetric electrically-charged particles is also discussed.

Magnetic monopole search, past and present

In the article by Arttu Rajantie on the search for magnetic monopoles, I noticed there was no mention of other monopole searches that had negative results. The most significant of those is the work by Luis Alvarez and his co-authors.11. P. H. Eberhard, R. R. Ross, L. W. Alvarez, R. D. Watt, Phys. Rev. D 4, 3260 (1971). https://doi.org/10.1103/PhysRevD.4.3260,22. R. R. Ross, P. H. Eberhard, L. W. Alvarez, R. D. Watt, Phys. Rev. D 8, 698 (1973). https://doi.org/10.1103/PhysRevD.8.698,33. L. W. Alvarez, P. H. Eberhard, R. R. Ross, R. D. Watt, in Proceedings of the Apollo 11 Lunar Science Conference, vol. 3, Pergamon Press (1970), p. 1953. The references to Rajantie’s figure 4, the plot of monopole flux versus monopole mass, cite experiments by Alvarez and his colleagues. A description of the implications of their work would have been helpful.ReferencesSection:ChooseTop of pageReferences <<CITING ARTICLES1. P. H. Eberhard, R. R. Ross, L. W. Alvarez, R. D. Watt, Phys. Rev. D 4, 3260 (1971). https://doi.org/10.1103/PhysRevD.4.3260, Google ScholarCrossref, ISI2. R. R. Ross, P. H. Eberhard, L. W. Alvarez, R. D. Watt, Phys. Rev. D 8, 698 (1973). https://doi.org/10.1103/PhysRevD.8.698, Google ScholarCrossref, ISI3. L. W. Alvarez, P. H. Eberhard, R. R. Ross, R. D. Watt, in Proceedings of the Apollo 11 Lunar Science Conference, vol. 3, Pergamon Press (1970), p. 1953. Google Scholar© 2017 American Institute of Physics.

Magnetic monopole search, past and present

Magnetic monopole search, past and present

Magnetic monopole search, past and present

Rajantie replies: Alfred Goldhaber raises an interesting point that the radius of a magnetic monopole has to be larger than its Compton wavelength. As with the ’t Hooft–Polyakov monopole, the nonzero size could be due to some new particles whose mass would have to be around 10–100 GeV for a TeV-scale monopole. So far the Large Hadron Collider (LHC) has produced no evidence of new particles beyond the standard model, but that does not necessarily rule out the existence of magnetic monopoles because we currently do not have a good enough theoretical understanding of the properties those particles would need to have.The requirement for a finite monopole size is a consequence of the monopole’s strong magnetic charge, and the electromagnetic duality means that the same conclusion would also apply to particles that have a strong electric charge. The strong charge means that the classical picture of a field around a static source may not apply, and hence the nonzero size could also be due to quantum mechanical effects without any new particles.Our theoretical understanding of strongly coupled quantum field theories is limited, but lattice field theory simulations11. M. Baig, H. Fort, J. B. Kogut, S. Kim, Phys. Rev. D 51, 5216 (1995). https://doi.org/10.1103/PhysRevD.51.5216 show that in its simplest form, quantum electrodynamics allows relatively strong charges, although not as strong as the Dirac charge of a magnetic monopole. The maximum charge allowed for a magnetic monopole in the standard model without any new particles is an interesting and still open theoretical question.Either way, the argument implies that if magnetic monopoles exist, they would have a nontrivial size and shape, which could be studied in future experiments.Because of space limitations, I could not do justice to the wide range of fascinating ways people have been trying to find magnetic monopoles. Christopher Harrison and Ken Frankel highlight some of the pioneering attempts. Although those searches did not produce positive results, they paved the way for future experiments, and their method of using a SQUID (superconducting quantum interference device) to search for monopoles is still being used in the MoEDAL experiment at the LHC.ReferencesSection:ChooseTop of pageReferences <<1. M. Baig, H. Fort, J. B. Kogut, S. Kim, Phys. Rev. D 51, 5216 (1995). https://doi.org/10.1103/PhysRevD.51.5216, Google ScholarCrossref© 2017 American Institute of Physics.

Magnetic monopole search, past and present

Magnetic monopole search, past and present

Physics reach of MoEDAL at LHC: magnetic monopoles, supersymmetry and beyond

MoEDAL is a pioneering experiment designed to search for highly ionising messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles, that are predicted to exist in a plethora of models beyond the Standard Model. Its ground-breaking physics program defines a number of scenarios that yield potentially revolutionary insights into such foundational questions as, are there extra dimensions or new symmetries, what is the mechanism for the generation of mass, does magnetic charge exist, what is the nature of dark matter, and, how did the big-bang develop at the earliest times. MoEDAL's purpose is to meet such far-reaching challenges at the frontier of the field. The physics reach of the existing MoEDAL detector is discussed, giving emphasis on searches for magnetic monopoles, supersymmetric (semi)stable partners, doubly charged Higgs bosons, and exotic structures such as black-hole remnants in models with large extra spatial dimensions and D-matter in some brane theories.

Search for ultrarelativistic magnetic monopoles with the Pierre Auger observatory

We present a search for ultra-relativistic magnetic monopoles with the Pierre Auger Observatory. Such particles, possibly a relic of phase transitions in the early universe, would deposit a large amount of energy along their path through the atmosphere, comparable to that of ultrahigh-energy cosmic rays (UHECRs). The air shower profile of a magnetic monopole can be effectively distinguished by the fluorescence detector from that of standard UHECRs. No candidate was found in the data collected between 2004 and 2012, with an expected background of less than 0.1 event from UHECRs. The corresponding 90% confidence level (C.L.) upper limits on the flux of ultra-relativistic magnetic monopoles range from $10^{-19}$ (cm$^{2}$ sr s)$^{-1}$ for a Lorentz factor $\gamma=10^9$ to $2.5 \times10^{-21}$ (cm$^{2}$ sr s)$^{-1}$ for $\gamma=10^{12}$. These results - the first obtained with a UHECR detector - improve previously published limits by up to an order of magnitude.