Monopoles from an Atmospheric Fixed Target Experiment.

A search for magnetic monopoles and high-electric-charge objects is presented using 34.4 fb^{-1} of 13TeV pp collision data collected by the ATLAS detector at the LHC during 2015 and 2016. The considered signature is based upon high ionization in the transition radiation tracker of the inner detector associated with a pencil-shape energy deposit in the electromagnetic calorimeter. The data were collected by a dedicated trigger based on the tracker high-threshold hit capability. The results are interpreted in models of Drell-Yan pair production of stable particles with two spin hypotheses (0 and 1/2) and masses ranging from 200 to 4000GeV. The search improves by approximately a factor of 5 the constraints on the direct production of magnetic monopoles carrying one or two Dirac magnetic charges and stable objects with electric charge in the range 20≤|z|≤60 and extends the charge range to 60<|z|≤100.

MoEDAL is a pioneering experiment designed to search for highly ionizing 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. It started data taking at the LHC at a centre-of-mass energy of 13 TeV, in 2015. MoEDAL’s 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; and what is the nature of dark matter. MoEDAL’s purpose is to meet such far-reaching challenges at the frontier of the field. We will present an overview of the MoEDAL detector, including the planned MAPP subdetector, as well as MoEDAL’s physics program. The concluding section highlights our first physics results on Magnetic Monopole production, that are the world’s best for Monopoles with multiple magnetic charge.

Search for neutrino-produced magnetic monopoles in a bubble chamber exposure

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19} cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with β≳0.8 and up to β∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

Search for magnetic monopoles with nuclear track detectors

Whereas MeV neutrin astronomy has been established by the observation of solar neutrinos and neutrinos from supernova SN1987, neutrinos with energies of GeV to PeV, which must accompany the production of high energy cosmic rays still await discovery. Detectors underground have turned ut to be too small to detect the feeble fluxes of energetic neutrinos from cosmic accelerators. The high‐energy frontier is being tackled by much larger, expandable arrays constructed in open water or ice. These telescopes detect the Cherenkov light generated by secondary particles – typically muons – produced in neutrino interactions. The Cherenkov radiation is detected by an array of photomultipliers which measures the arrival times of the photons to a precision of a few nanoseconds. Timing as well as amplitude information is used to reconstruct the track of the muon. To ensure that the muon is produced by a neutrino, the Earth is used as a filter: up‐going muon tracks can be generated only by neutrinos since this is the only particle which can pass through the Earth. Upgoing muons must be identified in an intense flux of downgoing muons. At 1 kilometer depth, the flux of downgoing (background) muons exceeds the upgoing signal by nearly six orders of magnitude.The Amanda neutrino detector consists of photomultipliers embedded at a depth of 1.5‐2.0 km in the ice sheet covering the geographic South Pole. The photomultipliers are housed in pressure glass spheres which are attached to vertical cable strings. With 677 photomultipliers at 19 strings, the present AMANDA‐II array reaches an effective detection area of a few 104 m2 for 1 TeV muons. Although still far below the square kilometer size suggested by most theoretical models, AMANDA‐II may be the first detector with a realistic discovery potential for extraterrestrial high‐energy neutrinos.First physically relevant limits have been obtained from the analysis of data taken with the three times smaller AMANDA‐B10 in 1997. The limit on the diffuse flux from unresolved sources with an assumed E—2 spectrum is of the order of 10—6 Eν—2 cm—2 s—1 sr—1 GeV—1, close to recent theoretical bounds. The flux limit on point sources with an E—2 spectrum at the northern sky (declination larger than 30 degrees) is of the order of 10—7 cm—2 s—1 for Eν &gt; 10 GeV. The overall sensitivity of AMANDA‐B10 has been verified by a sample of more than 200 events which is dominated by atmospheric neutrinos. These are neutrinos which have been generated by interactions of primary cosmic rays in the atmosphere at the other side of the Earth. Since their flux is known with an accuracy of about 20%, they serve as a standard candle to calibrate the telescope.The main purpose of Amanda is the search for neutrinos from cosmic acceleration processes in galactic sources like binary systems or supernova remnants (SNR), or extragalactic sources like active galactic nuclei (AGN) or gamma ray bursters (GRB). On top of that, questions closely related to particle physics are studied. They include the search for neutrinos from the annihilation of Weakly Interacting Massive Particles (WIMPs), the search for magnetic monopoles, or the investigation of neutrino oscillations, using neutrinos from accelerators, the atmosphere or extraterrestrial neutrinos.A magnetic monopole with unit magnetic Dirac charge g = 137/2 · e and velocities above the Cherenkov threshold in water (β &gt; 0.75) would emit Cherenkov radiation smoothly along its path, exceeding that of a bare relativistic muon by a factor of 8300. No event with this rather unique signature has been observed by Amanda, yielding a limit of 0.5 · 10—16 cm—2 s—1 sr—1 on the flux of relativistic magnetic monopoles. This value is 20 times smaller than the bound which is derived from the observed stability of galactic magnetic fields and nearly five times below earlier limits obtained by other direct search experiments.The annihilation of WIMPcandidates like neutralinos (the lightest supersymmetric particle) trapped within the core of the Earth or in the Sun would generate high‐energy neutrinos from the nearly vertical direction or from the Sun, respectively. Present searches by experiments underground and underwater for an excess of muons from the center of the Earth exclude a fraction of supersymmetric models with neutralin masses above 50‐100 GeV. Amanda performed a search for upgoing muons in a narrow cone around the opposite zenith. The number of events detected is consistent with the expectation from neutrinos produced by cosmic‐ray interactions in the atmosphere at the opposite hemisphere of the Earth. This measurements places a limit on the flux of neutrinos from neutralin annihilation. Indeed already the data from only 135 days taken in 1997 yields limits competitive to those derived from underground experiments over many years data collection.The ultimate goal of the Amanda collaboration is a detector of the scale of one cubic kilometer, named IceCube. This is the order of magnitude required by many models of neutrino production in active galactic nuclei, in gamma ray bursts, in the center of our galaxy or in young supernovae. This scale is als suggested by the pretention to open a really new window – i.e., to increase the sensitivity compared to existing devices by 2‐3 orders of magnitude. The proposed IceCube detector consists of 4800 photomultipliers at 80 strings. The deployment of the detector is scheduled to start in the austral summer 2002/03 and to extend over six years.

Magnetic monopoles have not been observed despite decades of efforts. KoreA Experiment on Magnetic Monopole (KAEM) is an experimental search for fundamental magnetic monopoles in the low-mass and low-charge regions. KAEM is configured with a thin aluminum target, Na-22 source, two 1 T·m solenoids, about 3 m long vacuum chamber, two electromagnetic calorimeters, and the trigger-veto detector. The LYSO, CsI, and CsI(Tl) crystals, used widely in nuclear/particle physics experiments, are candidates for the trigger-veto detector and electromagnetic calorimeters. We investigated the characteristics and the performance of those crystals to decide which type of crystal satisfies the requirements of our experiment. In addition, these crystals were tested with a customized DAQ system and Na-22, Cs-137, and Co-60 radioactive sources. This talk will present the characteristic of several types of crystals and beam test results obtained with the customized DAQ system.

A search for heavily ionizing particles produced in p̄p collisions at √s = 1.8 TeV was performed at the Fermilab Tevatron collider using plastic track detectors. No highly ionizing particles were observed. The experiment places a limit on the production of magnetic monopoles with mass m < 850 GeV at σ < 2·10-34 cm2 (95% confidence level). The level of radiation present in the collider tunnel is discussed.

Search for magnetic monopoles with MACRO

The existence of magnetic monopoles is an interesting theoretical possibility generically predicted by grand unified theories (GUTs). Based on over 8 years of data, the Pierre Auger Observatory reports no detection of monopoles but do set the best limits to date on the flux of ultrarelativistic intermediate-mass monopoles by looking for the distinctive signatures of monopole-induced air showers.

The magnetic monopole is a hypothetical particle, which is an important field configuration in many Grand Unified Theories, and whose mass may vary from 104 to 1018 GeV. The quantization of magnetic charge derived by Dirac in 1931 suggests the heavy ionization nature of magnetic monopoles. The NO$\nu$A collaboration is using the NO$\nu$A far detector - the largest scintillator detector in the world - to search for signals of relic monopoles that might have been produced in the early universe. To achieve this, we have simulated the propagation of non-relativistic monopoles with a uniform distribution of velocity within the range 10-4≲β≲ 0.2 , and the corresponding detector response. To record potential monopole-like events, we have developed a data-driven trigger system with two monopole triggers (the fast monopole trigger and the slow monopole trigger). This analysis focuses on the data recorded by the fast monopole trigger, which is sensitive to monopoles with velocity β ≳ 10-3. We have performed a blind analysis on a total live time of 1628.2 hours of data recorded by the fast monopole trigger. We present the updated flux limits with 90% CL (confidence level) as a function of monopole mass and velocity.

This article delves into the intricate fabric of the universe through the lens of symmetry breaking, the elusive search for magnetic monopoles, and the mathematical elegance of homotopy groups. Spontaneous symmetry breaking, pivotal in distinguishing fundamental forces, is illustrated by the Higgs mechanism within quantum field theory. The quest for magnetic monopoles, inspired by grand unified theories, challenges our understanding of electromagnetic symmetry, suggesting an exquisite balance between the electric and magnetic charges as per the Dirac quantization condition. Homotopy groups offer a profound mathematical framework to classify topological defects, enriching our understanding of the universes early conditions and the formation of cosmic structures. Despite extensive searches, direct evidence for magnetic monopoles remains elusive, propelling theoretical and experimental physics into new territories. This article synthesizes theoretical foundations, experimental endeavors, and the implications of these pursuits on our understanding of the cosmos.

The superstrong interaction between magnetic monopoles suppresses the production rate of free monopoles and antimonopoles below what one would expect on the basis of standard production models, since, even when a monopole and an antimonopole are created, it is very likely they will be drawn together and annihilate rather than escape each other. This makes it very difficult to search for them directly. In this paper we speculate on the feasibility of various techniques which could be used to infer the existence of monopoles indirectly. In particular, it may sometimes be possible to recognize a monopole-antimonopole annihilation by its products, which for our purposes we take to be showers of photons. Our conclusions as to the appropriateness of various methods as a function of monopole mass and (magnetic) charge are summarized in Fig. 2; the indirect methods are expected to be suited to look for monopoles of high magnetic charge.

The search for the magnetic monopoles predicted by grand unified theories continues, with smaller number of experiments and larger number of experimenters than was the case of a few years ago. This search is complicated by a variety of attributes the monopole might possess in addition to its magnetic charge. Our preconceptions about its mass and velocity are not to be trusted. It may or may not catalyze proton decay. It may have intrinsic electric charge, and if not it probably attached a proton at an early epoch. It is difficult to probe interesting flux levels with induction detectors, and the monopole’s other possible attributes complicate the analysis of all other experiments and astronomical observations. In this discussion we attempt to classify the available limits according to the input assumptions.

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.