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Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics

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A special issue of Universe (ISSN 2218-1997). This special issue belongs to the section "High Energy Nuclear and Particle Physics".

Deadline for manuscript submissions: closed (15 February 2023) | Viewed by 7471

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Special Issue Editors

Prof. Dr. Biagio Lucini

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Guest Editor

Department of Physics, Swansea University, Swansea SA2 8PP, UK
Interests: lattice gauge theory; theoretical particle physics; large-N gauge theories; 1/N expansion; strongly interacting BSM dynamics; glueballs; Monte Carlo algorithms; statistical mechanics of phase transitions; critical phenomena; strongly correlated electron systems

Dr. Chik Him Wong

E-Mail Website
Guest Editor

Physic Department, Bergische Universität Wuppertal, D-42119 Wuppertal, Germany
Interests: Lattice quantum chromodynamics (Lattice QCD); Beyond Standard Model (BSM); Dark Matter; Particle Physics; High Performance Computing (HPC)

Special Issue Information

Dear Colleagues,

The Standard Model (SM) in particle physics has been one of the most successful theories in the history of physics. However, it is widely believed that SM is incomplete and likely a mere effective field theory of some more fundamental theories at higher energies. It does not account for observed phenomena such as dark matter, dark energy,matter-antimatter asymmetry, neutrino mass etc. It also possesses theoretical puzzles such as strong CP problem, hierarchy problem etc.

Therefore there has been significant efforts for the search of new physics beyond standard model (BSM).

Strongly coupled gauge theories (SCGTs) are often proposed as BSM candidates. It is speculated that their bound states may serve as dark matters and their interactions with SM particles may solve some mysteries in SM. These theories behave vastly differently, depending on parameters such as the number of colors, flavors, fermion representations etc. In order to explore the parameter space and seek for those with the desired properties, their low-energy predictions such as hadron spectroscopy and beta-function in the infrared limit are of most interest. Since they are strongly coupled, such predictions can only be obtained by non-perturbative studies such as numerical simulations formulated by lattice gauge theory. As the most popular non-perturbative approach, lattice simulations were originally developed for the study of quantum chromodynamics(QCD), which is a SCGT. Thanks to rapid advancements of high performance computing (HPC) technology and algorithms in recent decades, lattice simulations have become mature and found applications in studies of other non-QCD SCGTs. Due to the non-QCD nature of the theories of interest, such applications impose new challenges and hence require new solutions and techniques.

This Special Issue focuses on the latest developments in numerical studies of SCGTs in the context of BSM physics, ranging from novel simulation techniques, formulation and algorithms to phenomenological consequences of BSM candidates such as dark matter spectroscopy and near-conformality. You are invited to submit contributions to this Special Issue with both original and review articles.

Prof. Dr. Biagio Lucini
Dr. Chik Him Wong
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Universe is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Dark matter (DM)
Beyond Standard Model (BSM)
Lattice gauge theory (LGT)
Strongly coupled gauge theory (SCGT)
High-performance computing (HPC)

Published Papers (6 papers)

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Research

Jump to: Review

26 pages, 573 KiB

Open AccessArticle

Holographic Non-Abelian Flavour Symmetry Breaking

by Johanna Erdmenger, Nick Evans, Yang Liu and Werner Porod

Universe 2023, 9(6), 289; https://doi.org/10.3390/universe9060289 - 14 Jun 2023

Cited by 5 | Viewed by 843

Abstract

We investigate a holographic model for both spontaneous and explicit symmetry breaking of non-abelian flavour symmetries. This consists of a bottom-up model inspired by the top-down D3/probe D7-brane model. It incorporates the running anomalous dimensions of the fields. We ensure that in the holographic bulk, the full non-abelian flavour symmetries for massless quarks are present. The quark masses are spontaneously generated field values in the bulk and there is a resultant bulk Higgs mechanism. We provide a numerical technique to find the mass eigenvalues from a system of mixed holographic fields, testing it against an analytic model of

N = 2

supersymmetric matter fields. We apply these ideas to two-flavour QCD with both

u - d

quark mass splitting and multi-trace bulk action terms that are expected to break U

{(N_{f})}_{V}

to SU(

N_{f})_{V} \times U {(1)}_{V}

away from large N. We also discuss three-flavour QCD with strange quark mass splitting and applications to more exotic symmetry breaking patterns of potential relevance for composite Higgs models. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

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Figure 1

13 pages, 290 KiB

Open AccessArticle

Higher-Spin Currents, Operator Mixing and UV Asymptotics in Large-N QCD-like Theories

by Marco Bochicchio

Universe 2023, 9(2), 57; https://0-doi-org.brum.beds.ac.uk/10.3390/universe9020057 - 17 Jan 2023

Viewed by 921

Abstract

We extend to operator mixing—specifically, to higher-spin twist-2 operators—the asymptotic theorem on the ultraviolet asymptotics of the spectral representation of 2-point correlators of multiplicatively renormalizable operators in large-N confining QCD-like theories. The extension is based on a recent differential geometric approach to operator mixing that involves the Poincaré-Dulac theorem and allows us to reduce generically the operator mixing to the multiplicatively renormalizable case, provided that

\frac{γ_{0}}{β_{0}}

is diagonalizable and a certain nonresonant condition for its eigenvalues holds according to the Poincaré-Dulac theorem, with

γ_{0}

and

β_{0}

the one-loop coefficients of the anomalous dimension matrix and beta function respectively. Relatedly, we solve a conundrum about the generic nonconservation of higher-spin currents versus the conservation—up to contact terms—of the corresponding free propagators in the spectral representation of 2-point correlators of higher-spin operators of pure integer spin to the leading large-N order. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

17 pages, 440 KiB

Open AccessArticle

Exploring Gauge Theories with Adjoint Matter on the Lattice

by Georg Bergner, Gernot Münster and Stefano Piemonte

Universe 2022, 8(12), 617; https://0-doi-org.brum.beds.ac.uk/10.3390/universe8120617 - 24 Nov 2022

Cited by 2 | Viewed by 831

Abstract

We review our efforts in investigating gauge theories with fermions in the adjoint representation of the gauge group by means of numerical simulations. These theories have applications in possible extensions of the standard model of particle physics, being a core part of supersymmetric gauge theories. They also play an important role in uncovering fundamental properties of strongly interacting theories due to distinct features, such as a substantially different phase diagram. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

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Figure 1

18 pages, 502 KiB

Open AccessArticle

Topological Gauge Actions on the Lattice as Overlap Fermion Determinants

by Nikhil Karthik and Rajamani Narayanan

Universe 2022, 8(6), 332; https://0-doi-org.brum.beds.ac.uk/10.3390/universe8060332 - 17 Jun 2022

Viewed by 1153

Abstract

Overlap fermion on the lattice has been shown to properly reproduce topological aspects of gauge fields. In this paper, we review the derivation of Overlap fermion formalism in a torus of three space-time dimensions. Using the formalism, we show how to use the Overlap fermion determinants in the massless and infinite mass limits to construct different continuum topological gauge actions, such as the level-k Chern–Simons action, “half-CS” term and the mixed Chern–Simons (BF) coupling, in a gauge-invariant lattice UV regulated manner. Taking special Abelian and non-Abelian background fields, we demonstrate numerically how the lattice formalism beautifully reproduces the continuum expectations, such as the flow of action under large gauge transformations. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

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Figure 1

Review

Jump to: Research

67 pages, 2758 KiB

Open AccessReview

Sp(2N) Lattice Gauge Theories and Extensions of the Standard Model of Particle Physics

by Ed Bennett, Jack Holligan, Deog Ki Hong, Ho Hsiao, Jong-Wan Lee, C.-J. David Lin, Biagio Lucini, Michele Mesiti, Maurizio Piai and Davide Vadacchino

Universe 2023, 9(5), 236; https://0-doi-org.brum.beds.ac.uk/10.3390/universe9050236 - 17 May 2023

Cited by 8 | Viewed by 1355

Abstract

We review the current status of the long-term programme of numerical investigation of

S p (2 N)

gauge theories with and without fermionic matter content. We start by introducing the phenomenological as well as theoretical motivations for this research programme, which [...] Read more.

We review the current status of the long-term programme of numerical investigation of

S p (2 N)

gauge theories with and without fermionic matter content. We start by introducing the phenomenological as well as theoretical motivations for this research programme, which are related to composite Higgs models, models of partial top compositeness, dark matter models, and in general to the physics of strongly coupled theories and their approach to the large-N limit. We summarise the results of lattice studies conducted so far in the

S p (2 N)

Yang–Mills theories, measuring the string tension, the mass spectrum of glueballs and the topological susceptibility, and discuss their large-N extrapolation. We then focus our discussion on

S p (4)

, and summarise the numerical measurements of mass and decay constant of mesons in the theories with fermion matter in either the fundamental or the antisymmetric representation, first in the quenched approximation, and then with dynamical fermions. We finally discuss the case of dynamical fermions in mixed representations, and exotic composite fermion states such as the chimera baryons. We conclude by sketching the future stages of the programme. We also describe our approach to open access. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

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Figure 1

18 pages, 592 KiB

Open AccessFeature PaperReview

Lattice Computations for Beyond Standard Model Physics

by Kari Rummukainen and Kimmo Tuominen

Universe 2022, 8(3), 188; https://0-doi-org.brum.beds.ac.uk/10.3390/universe8030188 - 17 Mar 2022

Cited by 6 | Viewed by 1532

Abstract

Understanding the dynamics of strongly coupled non-Abelian gauge theories constitutes one of the ongoing grand challenges in theoretical physics. This has been motivated by the need to understand long-distance behavior of quantum chromodynamics, and by the possible phenomenological applications in dynamical electroweak symmetry breaking or strongly coupled and composite dark sectors. In this review, we start by briefly outlining these motivations, and then discuss how first principle lattice methods have been adapted to provide results on vacuum phase diagrams of strongly coupled gauge theories with different gauge groups and various fermion representations. Full article

(This article belongs to the Special Issue Numerical Studies of Strongly Coupled Gauge Theories (SCGTs) in the Search of New Physics)

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