Dynamical Electroweak Symmetry Breaking

The phenomenon of dynamical symmetry breaking (DSB) in quantum field theory is discussed in a detailed and comprehensive way. The deep connection between this phenomenon in condensed matter physics and particle physics is emphasized. The realizations of DSB in such realistic theories as quantum chromodynamics and electroweak theory are considered. Issues intimately connected with DSB such as critical phenomenona and effective lagrangian approach are also discussed.

This is an expanded version of the report by the Electroweak Symmetry Breaking and Beyond the Standard Model Working Group which was contributed to Particle Physics — Perspectives and Opportunities, a report of the Division of Particles and Fields Committee for Long Term Planning. One of the Working Group's primary goals was to study the phenomenology of electroweak symmetry breaking and attempt to quantify the “physics reach” of present and future colliders. Their investigations encompassed the Standard Model — with one doublet of Higgs scalars — and approaches to physics beyond the Standard Model. These include models of low-energy supersymmetry, dynamical electroweak symmetry breaking, and a variety of extensions of the Standard Model with new particles and interactions. The Working Group also considered signals of new physics in precision measurements arising from virtual processes and examined experimental issues associated with the study of electroweak symmetry breaking and the search for new physics at present and future hadron and lepton colliders.This volume represents an important contribution to the efforts being made to advance the frontiers of particle physics.

With this thesis the author contributes to the development of a non-mainstream but long-standing approach to electroweak symmetry breaking based on an analogy with superconductivity. Electroweak symmetry breaking is assumed to be caused by dynamically generated masses of typical fermions, i.e., of quarks and leptons, which in turn assumes a new dynamics between quarks and leptons. Primarily it is designed to generate fermion masses and electroweak symmetry breaking is an automatic consequence. After the summary of the topic, the first main part of the thesis addresses the question as to whether the masses of known quarks and leptons provide sufficiently strong sources of electroweak symmetry breaking. It is demonstrated that neutrino masses subject to the seesaw mechanism are indispensable ingredients. The other two parts of the thesis are dedicated to the presentation of two particular models: The first model is based on the new strong Yukawa dynamics and serves as a platform for studying the ability to reproduce fermion masses. The second, more realistic model introduces a flavor gauge dynamics and its phenomenological consequences are studied. Even though, in the past, this type of models has already been of some interest, following the discovery of the Standard-Model-like Higgs particle, it is regaining its relevance.

The LHC is expected to fid new physics beyond the Standard Model (BSM). Technicolor models are a class of BSM models which involve a new strongly interacting sector responsible for electroweak symmetry breaking (EWSB). The phenomenological viability of these models depends on features such as the existence of an infrared fixed point (IRFP) at strong coupling, and the size of the mass anomalous dimension at this fixed point. As these features are at strong coupling they are not accessible to perturbative methods, and so need to be investigated non-perturbatively using lattice methods. In this thesis, two candidate Technicolor theories are investigated using two independent and complementary lattice methods, the Schrodinger Functional (SF) and the Monte Carlo Renormalisation Group (MCRG), to measure the running of the coupling and the anomalous mass dimension in these theories.

This book is a collection of original papers on dynamical gauge symmetry breaking, and is intended for graduate students and researchers in theoretical physics (elementary particle physics and others) who have an understanding of basic quantum field theory. The book can serve as a research text for those requiring an introduction to dynamical gauge symmetry breaking and as a reference text for active researchers. The important papers in the field that are included deal with attempts to apply the ideas to realistic models of elementary particle interactions. A historical critique by the editors provides an introductory review.