Abstract: In this dissertation I use lattice gauge theory to study models of electroweak symmetry breaking that involve new strong dynamics. Electroweak symmetry breaking (EWSB) is the process by which elementary particles acquire mass. First proposed in the 1960s, this process has been clearly established by experiments, and can now be considered a law of nature. However, the physics underlying EWSB is still unknown, and understanding it remains a central challenge in particle physics today. A natural possibility is that EWSB is driven by the dynamics of some new, strongly-interacting force. Strong interactions invalidate the standard analytical approach of perturbation theory, making these models difficult to study. Lattice gauge theory is the premier method for obtaining quantitatively-reliable, nonperturbative predictions from strongly-interacting theories. In this approach, we replace spacetime by a regular, finite grid of discrete sites connected by links. The fields and interactions described by the theory are likewise discretized, and defined on the lattice so that we recover the original theory in continuous spacetime on an infinitely large lattice with sites infinitesimally close together. The finite number of degrees of freedom in the discretized system lets us simulate the lattice theory using high-performance computing. Lattice gauge theory has long been applied to quantum chromodynamics, the theory of strong nuclear interactions. Using lattice gauge theory to study dynamical EWSB, as I do in this dissertation, is a new and exciting application of these methods. Of particular interest is non-perturbative lattice calculation of the electroweak S parameter. Experimentally S [approximate] -0.15(10), which tightly constrains dynamical EWSB. On the lattice, I extract S from the momentum-dependence of vector and axial-vector current correlators. I created and applied computer programs to calculate these correlators and analyze them to determine S . I also calculated the masses and other properties of the new particles predicted by these theories. I find S [Special characters omitted.] 0.1 in the specific theories I study. Although this result still disagrees with experiment, it is much closer to the experimental value than is the conventional wisdom S [Special characters omitted.] 0.3. These results encourage further lattice studies to search for experimentally viable strongly-interacting theories of EWSB.

This volume contains the Proceedings of'the International Workshop "Lattice Gauge Theory 1986", held at Brookhaven National Laboratory, September 15 - 19, 1986. The meeting was the sequel to the one held at Wuppertal in 1985, the Proceedings of which have appeared in the same Plenum series. During the past few years, a considerable number of meetings on lat tice gauge theory have been held, on both sides of the Atlantic. With our workshop, through early planning and coordination with other prospective organizers, we tried to channel this activity into one major yearly meeting. For 1986, these efforts were successful, and it is our hope that a pattern has been set for the coming years. One result, however, was that the number of participants considerably exceeded that normally found at NATO Advanced Research Workshops. This year, a "nucleus" of NATO-supported experts induced a large number of further interested specialists to obtain their own funds - thus greatly amplifying the impact of the event. The topics covered at the workshop ranged from hadron spectra to strong interaction thermo dynamics; they included spontaneous symmetry breaking and Higgs models, renormalization group methods, as well as many contributions on various possible schemes for the simulation of dynamical quarks. First systematic applications of finite size scaling to lattice gauge theory were discussed, and the approach to the continuum limit was considered in detail.

Almost all theories of fundamental interactions are nowadays based on the gauge concept. Starting with the historical example of quantum electrodynamics, we have been led to the successful unified gauge theory of weak and electromagnetic interactions, and finally to a non abelian gauge theory of strong interactions with the notion of permanently confined quarks. The. early theoretical work on gauge theories was devoted to proofs of renormalizability, investigation of short distance behaviour, the discovery of asymptotic freedom, etc . . , aspects which were accessible to tools extrapolated from renormalised perturbation theory. The second phase of the subject is concerned with the problem of quark confinement which necessitates a non-perturbative understanding of gauge theories. This phase has so far been marked by the introduc tion of ideas from geometry, topology and statistical mechanics in particular the theory of phase transitions. The 1979 Cargese Institute on "Recent Developments on Gauge Theories" was devoted to a thorough discussion of these non-perturbative, global aspects of non-abelian gauge theories. In the lectures and seminars reproduced in this volume the reader wilf find detailed reports on most of the important developments of recent times on non perturbative gauge fields by some of the leading experts and innovators in this field. Aside from lectures on gauge fields proper, there were lectures on gauge field concepts in condensed matter physics and lectures by mathematicians on global aspects of the calculus of variations, its relation to geometry and topology, and related topics.

This book provides a broad introduction to gauge field theories formulated on a space-time lattice, and in particular of QCD. It serves as a textbook for advanced graduate students, and also provides the reader with the necessary analytical and numerical techniques to carry out research on his own. Although the analytic calculations are sometimes quite demanding and go beyond an introduction, they are discussed in sufficient detail, so that the reader can fill in the missing steps. The book also introduces the reader to interesting problems which are currently under intensive investigation. Whenever possible, the main ideas are exemplified in simple models, before extending them to realistic theories. Special emphasis is placed on numerical results obtained from pioneering work. These are displayed in a great number of figures. Beyond the necessary amendments and slight extensions of some sections in the third edition, the fourth edition includes an expanded section on Calorons — a subject which has been under intensive investigation during the last twelve years.

This volume contains contributions to the workshop, which was largely focused on the strong coupling gauge theories in search for theories beyond the standard model, particularly, the LHC experiments and lattice studies of conformal fixed point. The main topics include walking technicolor and the role of conformality in view of the 125 GeV Higgs as a light composite Higgs (technidilaton, and other composite Higgs, etc.). Nonperturbative studies like lattice simulations and stringy/holographic approaches are extensively discussed in close relation to the phenomenological studies.After the discovery of 125 GeV Higgs at LHC, the central issue of particle physics is now to reveal the dynamical origin of the Higgs itself. One of the possibilities would be the composite Higgs based on the strong coupling gauge theory in the TeV region, such as the technidilaton predicted in walking technicolor with infrared conformality. The volume contains, among others, many of the latest important reports on walking technicolor and related subjects in the general context of conformality, in a way of direct relevance to the LHC phenomenology as well as the lattice studies. It is very timely to study full theoretical implications in the exciting era when the LHC is vigorously working. This volume is of great importance for that purpose.Speakers of 40 talks (plus posters) include K-I Aoki, Y Aoki, K Bamba, E Bennett, R S Chivukula, H Georgi, A Hasenfratz, D-K Hong, K Itoh, D Elander, G Fleming, H Fukano, Y Iwasaki, M Jarvinen, D Kadoh, S Kim, R Kitano, K-I Kondo, J Kuti, D Lin, N Maru, H Matsufuru, S Matsuzaki, K-I Nagai, C Nonaka, H Ohki, E Pallante, M Rho, E Rinaldi, F Sannino, D Schaich, A Shibata, R E Shrock, E H Simmons, K Tuominen, C H Wong, N Yamada, M J S Yang, and K Yamawaki.

This book introduces the reader to an area of elementary particle physics which has been the subject of intensive research in the past two decades. It provides graduate students with the basic theoretical background on quantum gauge field theories formulated on a space-time lattice, and with the computational tools for carrying out research in this field. The book is a substantially extended version of the first edition which appeared in 1992. Much effort has been invested to present the material in a transparent way, and in exemplifying subtle points in simple models. The material covered should enable the reader to follow the vast literature on the subject without too much difficulties. Hopefully the book will motivate young physicists to carry out research in this area of elementary particle physics.

- Wherever possible simple examples, which illustrate the main ideas, are provided before embarking on the actual discussion of the problem of interest - The book introduces the readers to problems of great current interest, like instantons, calorons, vortices, magnetic monopoles - QCD at finite temperature is discussed at great length, both in perturbation theory and in Monte Carlo simulations - The book contains many figures showing numerical results of pioneering work

This book introduces a large number of topics in lattice gauge theories, including analytical as well as numerical methods. It provides young physicists with the theoretical background and basic computational tools in order to be able to follow the extensive literature on the subject, and to carry out research on their own. Whenever possible, the basic ideas and technical inputs are demonstrated in simple examples, so as to avoid diverting the readers' attention from the main line of thought. Sufficient technical details are however given so that he can fill in the remaining details with the help of the cited literature without too much effort.This volume is designed for graduate students in theoretical elementary particle physics or statistical mechanics with a basic knowledge in Quantum Field Theory.

This volume presents the important recent progress in both theoretical and phenomenological issues of strong coupling gauge theories, with/without supersymmetry and extra dimensions, etc. Emphasis is placed on dynamical symmetry breaking with large anomalous dimensions governed by the dynamics near the nontrivial fixed point. Also presented are recent developments of the corresponding effective field theories, such as those including light spectra other than the NambuOCoGoldstone particles. This book is a must for all those who are interested in dynamical symmetry breaking and effective field theories in a modern version. Contents: Light-Front Quantization of Gauge Theories (S J Brodsky); Significance of the Renormalization Constant of the Color Gauge Field (K Nishijima & M Chaichian); Mass Gap and Color Confinement in YangOCoMills Theory Based on Asymptotic Solutions of SD Equation (K-I Kondo); Strong Coupling Approach to Transverse Lattice QCD (S Dalley); Vector Manifestation of Chiral Symmetry (M Harada); Locking Internal and Space-Symmetries: Relativistic Vector Condensation (F Sannino); A Practical Gauge Invariant Construction of Abelian Chiral Gauge Theories on the Lattice (Y Kikukawa); Neutrino Masses in Theories with Dynamical Breaking of Electroweak and Extended Gauge Symmetries (T Appelquist & R Schrock); Dynamical Electroweak Symmetry Breaking from Extra Dimensions (M Hashimoto et al.); Classical Solutions of Field Equations in Randall Sundrum Brane Worlds (D Karasik et al.); Flavor Constraints on Theory Space (E H Simmons et al.); Neutrino Mass Matrix in Terms of Up-Quark Masses (M Bando & M Obara); and other papers. Readership: Graduate students and researchers in high energy physics, particularly those interested in dynamical symmetry breaking and effective field theories."

"This volume contains the proceedings of the workshop "Crossing the Boundaries: Gauge Dynamics at Strong Coupling", hosted by the William I. Fine Theoretical Physics Institute at the University of Minnesota, May 14 - 17, 2009. The workshop honored the 60th birthday of Professor Misha Shifman and his outstanding achievements in the field of gauge dynamics. The meeting attracted a fascinating group of researchers working on the cutting edge of dynamics of gauge theories, including supersymmetric and stringtheories. Their talks covered a wide area of recent developments in the field."--Publisher's website.