Topological Avatars Of New Physics Research Articles

Machine learning techniques for detecting topological avatars of new physics.

The search for highly ionizing particles in nuclear track detectors (NTDs) traditionally requires experts to manually search through samples in order to identify regions of interest that could be a hint of physics beyond the standard model of particle physics. The advent of automated image acquisition and modern data science, including machine learning-based processing of data presents an opportunity to accelerate the process of searching for anomalies in NTDs that could be a hint of a new physics avatar. The potential for modern data science applied to this topic in the context of the MoEDAL experiment at the large Hadron collider at the European Centre for Nuclear Research, CERN, is discussed. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

The MoEDAL experiment: a new light on the high-energy frontier.

MoEDAL is a pioneering LHC experiment designed to search for anomalously ionizing messengers of new physics, such as the magnetic monopole. After a test run at 8 TeV centre-of-mass energy (Ecm), it started official data taking at the LHC at an Ecm of 13 TeV, in 2015. Its groundbreaking 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; do topological particles exist; and what is the nature of dark matter? After a brief introduction, MoEDAL's progress to date will be reported, including its past, current and expected future physics output. Additionally, an upgrade to the MoEDAL detector consisting of two new subdetectors: MAPP (MoEDAL Apparatus for Penetrating Particles) now being prototyped at IP8; and MALL (MoEDAL Apparatus for very long-lived particles), will be presented. Finally, a possible astroparticle extension to MoEDAL, called Cosmic-MoEDAL, will be briefly described. This high altitude detector will allow the search for magnetic monopoles to be continued from the TeV scale to the GUT scale. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Searching for supersymmetry and its avatars.

Why continue looking for supersymmetry? Over and above the aesthetic and theoretical motivations from string theory, there are several longstanding pheno- menological motivations for TeV-scale super- symmetry, such as the electroweak scale, and the lightest supersymmetric particle as cold dark matter. Run 1 of the Large Hadron Collider (LHC) has actually provided three extra motivations, namely the stabilization of the electroweak vacuum, and successful predictions for the Higgs mass and couplings. How to look for it? There are several examples of emergent supersymmetry, the most recent being on the surfaces of topological insulators, and some sort of effective supersymmetry could be useful for boosting the power of laser arrays. At the LHC, attention is moving towards signatures that had previously been neglected, such as long-lived charged particles-which might be an opportunity for the MoEDAL experiment. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Black holes in the quantum universe.

A succinct summary is given of the problem of reconciling observation of black hole-like objects with quantum mechanics. If quantum black holes behave like subsystems, and also decay, their information must be transferred to their environments. Interactions that accomplish this with 'minimal' departure from a standard description are parametrized. Possible sensitivity of gravitational wave or very long baseline interferometric observations to these interactions is briefly outlined. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

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'.

Primordial black holes and the origin of the matter-antimatter asymmetry.

We review here a new scenario of hot spot electroweak baryogenesis where the local energy released in the gravitational collapse to form primordial black holes (PBHs) at the quark-hadron (QCD) epoch drives over-the-barrier sphaleron transitions in a far from equilibrium environment with just the standard model CP violation. Baryons are efficiently produced in relativistic collisions around the black holes and soon redistribute to the rest of the universe, generating the observed matter-antimatter asymmetry well before primordial nucleosynthesis. Therefore, in this scenario there is a common origin of both the dark matter to baryon ratio and the photon to baryon ratio. Moreover, the sudden drop in radiation pressure of relativistic matter at H0/W±/Z0 decoupling, the QCD transition and e+e- annihilation enhances the probability of PBH formation, inducing a multi-modal broad mass distribution with characteristic peaks at 10-6, 1, 30 and 106 M⊙, rapidly falling at smaller and larger masses, which may explain the LIGO-Virgo black hole mergers as well as the OGLE-GAIA microlensing events, while constituting all of the cold dark matter today. We predict the future detection of binary black hole (BBH) mergers in LIGO with masses between 1 and 5 M⊙, as well as above 80 M⊙, with very large mass ratios. Next generation gravitational wave and microlensing experiments will be able to test this scenario thoroughly. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Monopole-antimonopole: interaction, scattering and creation.

The interaction of a magnetic monopole-antimonopole pair depends on their separation as well as on a second 'twist' degree of freedom. This novel interaction leads to a non-trivial bound state solution known as a sphaleron and to scattering in which the monopole-antimonopoles bounce off each other and do not annihilate. The twist degree of freedom also plays a role in numerical experiments in which gauge waves collide and create monopole-antimonopole pairs. Similar gauge wavepacket scatterings in the Abelian-Higgs model lead to the production of string loops that may be relevant to superconductors. Ongoing numerical experiments to study the production of electroweak sphalerons that result in changes in the Chern-Simons number, and hence baryon number, are also described but have not yet met with success. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

The inevitability of sphalerons in field theory.

The topological structure of field theory often makes inevitable the existence of stable and unstable localized solutions of the field equations. These are minima and saddle points of the energy. Saddle point solutions occurring this way are known as sphalerons, and the most interesting one is in the electroweak theory of coupled W, Z and Higgs bosons. The topological ideas underpinning sphalerons are reviewed here. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Monopole-antimonopole pair production by magnetic fields.

Quantum electrodynamics predicts that in a strong electric field, electron-positron pairs are produced by the Schwinger process, which can be interpreted as quantum tunnelling through the Coulomb potential barrier. If magnetic monopoles exist, monopole-antimonopole pairs would be similarly produced in strong magnetic fields by the electromagnetic dual of this process. The production rate can be computed using semiclassical techniques without relying on perturbation theory, and therefore it can be done reliably in spite of the monopoles' strong coupling to the electromagnetic field. This article explains this phenomenon and discusses the bounds on monopole masses arising from the strongest magnetic fields in the universe, which are in neutron stars known as magnetars and in heavy ion collision experiments such as lead-lead collisions carried out in November 2018 in the large Hadron collider at CERN. It will also discuss open theoretical questions affecting the calculation. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Physical implications of electroweak monopole.

The electroweak monopole in the standard model, the existence, characteristic features, cosmological production and physical implications are discussed. The discovery of the Higgs particle has been thought to be the 'final' test of the standard model. If the standard model is correct, however, it must have the electroweak monopole as the electroweak generalization of the Dirac monopole. This means that the detection of this monopole should become the final and topological test of the standard model. If detected, it becomes the first magnetically charged and stable topological elementary particle in the history of physics. Moreover, it has deep implications in physics. In cosmology, it could generate the primordial magnetic black holes which could explain the dark matter, become the seed of the large-scale structures of the universe, and be the source of the intergalactic magnetic field. Just as importantly, it could generate the hitherto unknown magnetic current which could have huge practical applications. Furthermore, the existence of the monopole requires us to reformulate the perturbative expansion in quantum field theory. This makes the detection of the electroweak monopole a most urgent issue. We discuss useful tips for the MoEDAL detector at LHC and similar experiments on how to detect the monopole successfully. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Searching for long-lived particles at the Large Hadron Collider and beyond.

We discuss the hunt for long-lived particles at the Large Hadron Collider. A motivation is given for such searches, and the experimental challenges are presented. It has become clear in the last few years that the present experiments are not optimally equipped to cover the full phase space of possibilities for such scenarios, so recently small additional experiments have been proposed for specific searches. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Searches for exotica and dark matter with neutrino telescopes.

Neutrino telescopes are designed to search for neutrino sources in the Universe, exploiting the Cherenkov light emitted along the path of the charged particles produced in interactions occurring close to the detector volume. Their huge size and the shield offered by large water or ice overburden make them excellent tools to search for exotic and rare particles in the cosmic radiation. In particular, they are sensitive to particles not predicted by the Standard Model that could be messenger of new physics. An overview of the experimental scenario and the relevant results obtained looking for magnetic monopoles, dark matter candidates and other exotic relic particles with neutrino telescopes is given, together with the description of possible new perspectives. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Topological avatars of new physics.

Topological avatars of new physics.

Cosmological evolution of semilocal string networks.

Semilocal strings-a particular limit of electroweak strings-are an interesting example of a stable non-topological defect whose properties resemble those of their topological cousins, the Abrikosov-Nielsen-Olesen vortices. There is, however, one important difference: a network of semilocal strings will contain segments. These are 'dumbbells' whose ends behave almost like global monopoles that are strongly attracted to one another. While closed loops of string will eventually shrink and disappear, the segments can either shrink or grow, and a cosmological network of semilocal strings will reach a scaling regime. We discuss attempts to find a 'thermodynamic' description of the cosmological evolution and scaling of a network of semilocal strings, by analogy with well-known descriptions for cosmic strings and for monopoles. We propose a model for the time evolution of an overall length scale and typical velocity for the network as well as for its segments, and some supporting (preliminary) numerical evidence. This article is part of a discussion meeting issue 'Topological avatars of new physics'.