Search for Magnetic Monopoles and Stable High-Electric-Charge Objects in 13 Tev Proton-Proton Collisions with the ATLAS Detector
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Emergence of low-energy monopole strength in the neutron-rich calcium isotopes
Not Available
Piekarewicz, J.↗
Effective model of QCD magnetic monopoles from numerical study of one- and two-component Coulomb quantum Bose gases
Not Available
Ramamurti, Adith↗
Designing phase sensitive probes of monopole superconducting order
Distinct from familiar s-, p-, or d-wave pairings, the monopole superconducting order represents a novel class of pairing order arising from nontrivial monopole charge of the Cooper pair. In the weak-coupling regime, this order can emerge when pairing occurs between Fermi surfaces with different Chern numbers in, for example, doped Weyl semimetal systems. However, the phase of monopole pairing order is not well-defined over an entire Fermi surface, making it challenging to design experiments sensitive to both its symmetry and topology. To address this, we propose a scheme based on symmetry and topological principles to identify this elusive pairing order through a set of phase-sensitive Josephson experiments. By examining the discrepancy between global and local angular momentum of the pairing order, we can unveil the monopole charge of the pairing order, including for models with higher pair monopole charge |q p |=1,2, and 3. We demonstrate the proposed probe of monopole pairing order through analytic and numerical studies of Josephson coupling in models of monopole superconductor junctions. This work opens a promising avenue to uncover the unique topological properties of monopole pairing orders and to distinguish them from known pairing orders based on spherical harmonic symmetry.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Measuring global monopole velocities, one by one
We present an estimation of the average velocity of a network of global monopoles in a cosmological setting using large numerical simulations. In order to obtain the value of the velocity, we improve some already known methods, and present a new one. This new method estimates individual global monopole velocities in a network, by means of detecting each monopole position in the lattice and following the path described by each one of them. Using our new estimate we can settle an open question previously posed in the literature: velocity-dependent one-scale (VOS) models for global monopoles predict two branches of scaling solutions, one with monopoles moving at subluminal speeds and one with monopoles moving at luminal speeds. Previous attempts to estimate monopole velocities had large uncertainties and were not able to settle that question. Our simulations find no evidence of a luminal branch. We also estimate the values of the parameters of the VOS model. With our new method we can also study the microphysics of the complicated dynamics of individual monopoles. Finally we use our large simulation volume to compare the results from the different estimator methods, as well as to asses the validity of the numerical approximations made.
79 ASTRONOMY AND ASTROPHYSICS↗
Elastic colloidal monopoles and reconfigurable self-assembly in liquid crystals
Monopole-like electrostatic interactions are ubiquitous in condensed matter, but they are often screened by counter-ions and cannot be switched from attractive to repulsive. In colloidal science, where the main goal is to develop colloidal particles that mimic and exceed the diversity and length scales of atomic and molecular assembly, electrostatically charged particles cannot change the sign of their surface charge or transform from monopoles to higher-order multipoles. In liquid-crystal colloids, elastic interactions between particles arise to minimize the free energy associated with elastic distortions in the long-range alignment of rod-like molecules around the particles. In dipolar quadrupolar and hexadecapolar nematic colloids, the symmetries of such elastic distortions mimic both electrostatic multipoles and the outermost occupied electron shells of atoms. Electric and magnetic switching, spontaneous transformations and optical control of elastic multipoles, as well as their interactions with topological defects and surface boundary conditions, have been demonstrated in such colloids. However, it has long been understood that elastic monopoles should relax to uniform or higher-order multipole states because of the elastic torques that they induce. We develop nematic colloids with strong elastic monopole moments and with elastic torques balanced by the optical torques induced by ambient light. We demonstrate the monopole-to-quadrupole reconfiguration of these colloidal particles by unstructured light, which resembles the driving of atoms between the ground state and various excited states. We show that the sign of the elastic monopoles can be switched, and that like-charged monopoles attract whereas oppositely charged ones repel, unlike in electrostatics. We also demonstrate the out-of-equilibrium dynamic assembly of these colloidal particles. This diverse and surprising behaviour is explained using a model that considers the balance of the optical and elastic torques that are responsible for the excited-state elastic monopoles and may lead to light-powered active-matter systems and self-assembled nanomachines.
36 MATERIALS SCIENCE↗
Monopoles, strings, and necklaces in SO(10) and E 6
We employ a variety of symmetry breaking patterns in SO(10) and E 6 Grand Unified Theories to demonstrate the appearance of topological defects including magnetic monopoles, strings, and necklaces. We show that independent of the symmetry breaking pattern, a topologically stable superheavy monopole carrying a single unit of Dirac charge as well as color magnetic charge is always present. Lighter intermediate mass topologically stable monopoles carrying two or three quanta of Dirac charge can appear in SO(10) and E 6 models respectively. These lighter monopoles as well as topologically stable intermediate scale strings can survive an inflationary epoch. We also show the appearance of a novel necklace configuration in SO(10) broken to the Standard Model via SU(4) c × SU(2) L × SU(2) R . It consists of SU(4) c and SU(2) R monopoles connected by flux tubes. Necklaces consisting of monopoles and antimonopoles joined together by flux tubes are also identified. Even in the absence of topologically stable strings, a monopole-string system can temporarily appear. This system decays by emitting gravity waves and we provide an example in which the spectrum of these waves is strongly peaked around 10 –4 Hz with Ω qw h 2 ≃10 –12 . This spectrum should be within the detection capability of LISA.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Monopole search below the Parker limit with the MACRO detector at Gran Sasso
The MACRO detector approved for the Gran Sasso Underground Laboratory in Italy will be the first capable of performing a definitive search for super-massive grand unified theory (GUT) monopoles at a level significantly below the Parker flux limit of 10 to the minus 15th power square centimeters Sr(-1) 5(-1). GUT monopoles will move at very low velocities (V approx. 0.001 c) relative to the Earth and a multifaceted detection technique is required to assume their unambiguous identification. Calculations of scintillator response to slow monopoles and measurements of scintillation efficiency for low energy protons have shown that bare monopoles and electrically charged monopoles moving at velocities as low as 5 x .0001 c will produce detectable scintillation signals. The time-of-flight between two thick (25 cm) liquid scintillation layers separated by 4.3m will be used in conjunction with waveform digitization of signals of extended duration in each thick scintillator to provide a redundant signature for slow penetrating particles. Limited streamer tubes filled with He and n-pentane will detect bare monopoles with velocities as low as 1 x 0.0001 c by exploiting monopole induced level mixing and the Penning effect.
Tarle, G.↗
Magnetic monopole plasma oscillations and the survival of Galactic magnetic fields
This paper explores the general nature of magnetic-monopole plasma oscillations as a theoretical possibility for the observed Galactic magnetic field in the presence of a high abundance of magnetic monopoles. The modification of the hydromagnetic induction equation by the monopole oscillations produces the half-velocity effect, in which the magnetic field is transported bodily with a velocity midway between the motion of the conducting fluid and the monopole plasma. Observational studies of the magnetic field in the Galaxy, and in other galaxies, exclude the half-velocity effect, indicating that the magnetic fields is not associated with monopole oscillations. In any case the phase mixing would destroy the oscillations in less than 100 Myr. The conclusion is that magnetic monopole oscillations do not play a significant role in the galactic magnetic fields. Hence the existence of galactic magnetic fields places a low limit on the monopole flux, so that their detection - if they exist at all - requires a collecting area at least as large as a football field.
Parker, E. N.↗
Search for Slow Magnetic Monopoles with the NOνA Far Detector
The magnetic monopole is a hypothetical particle with a magnetic charge. It is an important field configuration in many Grand Unified Theories. Dirac in 1931 derived a charge quantization condition, which suggests that the existence of one magnetic monopole in the universe will explain electric charge quantization. Since then, a search of the elusive particle has begun, and yet all came with negative results. The NO$\nu$A Far Detector is able to probe some of the parameter space for the search for monopoles. To achieve this, two dedicated triggers, one for fast monopoles and the other for slow monopoles, have been developed to record signals. Results for the first 8 months of high-gain slow monopole data were obtained, and a 90\% CL limit was established with no monopole observed. The analysis in this thesis is focused on new data with a higher gain, and we have explored potential improvement in efficiency and improvements in the reconstruction algorithm. We have done this an alysis on Monte-Carlo generated simulated data to establish efficiencies and examined a control set of the new data to understand its differences from the old.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Q-monopole-ball: a topological and nontopological soliton
Magnetic monopoles and Q-balls are examples of topological and nontopological solitons, respectively. A new soliton state with both topological and nontopological charges is shown to also exist, given a monopole sector with a portal coupling to an additional scalar field S with a global U(1) symmetry. This new state, the Q-monopole-ball, is more stable than an isolated Q-ball made of only S particles, and it could be stable against fissioning into monopoles and free Sparticles. Stable Q-monopole-balls can contain large magnetic charges, providing a novel nongravitational mechanism for binding like-charged monopoles together. They could be produced from a phase transition in the early universe and account for all dark matter.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Ionization-based search for magnetic monopoles using the NOvA Far Detector
We report a search for highly ionizing magnetic monopoles in the cosmic-ray flux using a 2713-day dataset collected during 2015–2025 with the NOvA Far Detector, a 14-kt segmented detector located on Earth’s surface in Minnesota, United States. The search is sensitive to monopoles across a wide range of speeds, 7 × 10 −4 < 𝛽 < 0.995, and is sensitive to masses as low as 2 × 10 5 GeV for the fastest monopoles. No signal was observed. With the detector’s large surface area and minimal overburden, we achieve the strongest flux limits reported to date in several regions of speed and mass. For heavy monopoles with masses above 10 13 GeV that are able to reach the detector from above or—crossing Earth—from below, we find a flux limit 𝜙 90% < 2 × 10 −16 cm −2 s −1 sr −1 (90% confidence level) for monopoles with 0.005 < 𝛽 < 0.8. Across the same range of speeds, we report a limit 𝜙 90% < 8 × 10 −16 cm −2 s −1 sr −1 for light monopoles with masses above 10 8 GeV that can reach the detector from above.
magnetic monopoles↗
Energetics of monopole production
The relativistic kinematics of monopole production and mechanisms of energy loss and gain for monopoles in free space and in the upper atmosphere are studied. It is shown that a monopole produced in a nuclear interaction must have a laboratory energy greater than about 200,000 GeV if its mass is greater than 600 GeV per sq cm. A study of energy loss mechanisms of such an energetic monopole in the earth's magnetic field and atmosphere rules out the possibility of observing such a monopole with the parameters observed by Price et al. (1975). The very low velocity of the observed monopole also makes an extraterrestrial production mechanism very unlikely.
Badhwar, G. D.↗
Kinematic constraints on the production of magnetic monopoles
A strict lower limit is derived for the laboratory kinetic energy of a magnetic monopole produced from a target at rest. The production of a monopole-antimonopole pair via the collision of a projectile with a target at rest in the laboratory is analyzed in terms of the velocity of the zero-momentum frame, the velocity of the monopole in that frame, and the velocity of the monopole in the laboratory. The limit obtained is applied to the data of Price et al. (1975), and almost all means of producing the monopole in the atmosphere immediately above the balloon-borne detectors are ruled out. Some mechanisms for slowing a monopole following its production are briefly considered.
Wilson, L. W.↗
Milli-magnetic monopole dark matter and the survival of galactic magnetic fields
A bstract Dark sectors with Abelian gauge symmetries can interact with ordinary matter via kinetic mixing. In such scenarios, magnetic monopoles of a broken dark U(1) will appear in our sector as confined milli-magnetically charged objects under ordinary electromagnetism. Halo ellipticity constraints are shown to significantly bound the strength of dark magnetic Coulomb monopole interactions. The bound magnetic monopole ground state, which in vacuum is stable and has no magnetic charge or moment, is shown to become quantum mechanically unstable in the presence of an external, ordinary magnetic field. If these states contribute sizably to the local dark matter density, they extract significant energy from the galactic magnetic field. We revise and extend this “Parker Bound” on galactic magnetic energy loss to milli-magnetic monopoles which leads to the strongest existing constraints on these states, satisfying our halo ellipticity bounds, over a wide range of magnetic monopole masses.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Pre-ADS superpotential from confined monopoles
According to the standard lore only single monopoles contribute to the superpotential on the Coulomb branch of 3D N=2 SUSY gauge theories. However we argue that multi-monopole configurations can also generate superpotential terms in the presence of squark VEVs on the mixed Higgs-Coulomb branch. The new ingredient is the confinement of monopoles via Nielsen-Olesen flux tubes. Such confined multi-monopoles will yield a pre-ADS superpotential which depends both on the local Coulomb moduli and matter superfields but has no fractional powers. Once the lifted moduli are integrated out the familiar ADS superpotential is obtained. Our results demonstrate the important role multi-monopoles can play in generating non-perturbative effects and also sheds light on the still somewhat mysterious dynamical origin of the general 4D ADS superpotential.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
The metamorphosis of semi-classical mechanisms of confinement: from monopoles on ℝ 3 × S 1 to center-vortices on ℝ 2 × T 2
There are two distinct regimes of Yang-Mills theory where we can demonstrate confinement, the existence of a mass gap, and the multi-branch structure of the effective potential as a function of the theta angle using a reliable semi-classical calculation. The two regimes are deformed Yang-Mills theory on ℝ 3 × S 1 , and Yang-Mills theory on ℝ 2 × T 2 where the torus is threaded by a ’t Hooft flux. The weak coupling regime is ensured by the small size of the circle or torus. In the first case the confinement mechanism is related to self-dual monopoles, whereas in the second case self-dual center-vortices play a crucial role. These two topological objects are distinct. In particular, they have different mutual statistics with Wilson loops. On the other hand, they carry the same topological charge and action. We consider the theory on ℝ × T 2 × S 1 and extrapolate both the monopole and vortex regimes to a quantum mechanical domain, where a cross-over takes place. Both sides of the cross-over are described by a deformed ℤ N TQFT. On ℝ 2 × S 1 × S 1 , we derive an effective field theory (EFT) of vortices from the EFT of monopoles in the presence of a ’t Hooft flux. This construction is based on a two-stage Higgs mechanism, reducing SU(N) to U(1) N−1 in 3d first, followed by reduction to a ℤ N EFT in 2d in the second step. This result shows how monopoles transmute into center-vortices, and suggests adiabatic continuity between the two confinement mechanisms. The basic mechanism is flux fractionalization: the magnetic flux of the monopoles splits up and is collimated in such a way that 2d Wilson loops detect it as a center vortex.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗