Fields Symmetries And Quarks

This revised and extended edition of the book Fields, Symmetries, and Quarks, originally published by McGraw-Hill Book Company, Hamburg, 1989, contains a new chapter on electroweak interactions which has also grown out of lectures that I have given in the meantime. In addition, a number of changes, mainly in the metric used, in the discussion of the theory of strong interactions, QCD, and in the chapter on hadron physics, have been made and errors have been corrected. The motivation for this book, however, is still the same as it was 10 years ago: This is a book on quantum field theory and our present understanding of leptons and hadrons for advanced students and the non-specialists and, in particular, the experimentalists working on problems of nuclear and hadron physics. I am grateful to Dr. S. Leupold for a very careful reading of the revised manuscript, many corrections, and helpful suggestions and to C. Traxler for producing the figures and for constructive discussions.

The structure of light hadrons is dominated by the spontaneously broken chiral symmetry of the strongly interacting (QCD) vacuum. Low energy properties of light hadrons can be described in terms of quarks interacting with chiral fields. This book gives a comprehensive account of a large class of models which describe the restoration of chiral symmetry at high temperature and density, the effective interactions between quarks, mesons as solutions of the Beth-Salpeter equation, and baryons in terms of solitions which rotate in flavor space. An in-depth analysis of regularization is given, including regularization by delocalized fields. Symmetry conserving approximations are formulated using both path integral and Feynmann graph methods. The book's style is pedagogical and well-suited to graduate and Ph.D. students who want to learn the techniques used in present day research. It can also serve as a reference for research and lecture courses.

The development in our understanding of symmetry principles is reviewed. Many symmetries, such as charge conjugation, parity and strangeness, are no longer considered as fundamental but as natural consequences of a gauge field theory of strong and electromagnetic interactions. Other symmetries arise naturally from physical models in some limiting situation, such as for low energy or low mass. Random dynamics and attempts to explain all symmetries ? even Lorentz invariance and gauge invariance ? without appealing to any fundamental invariance of the laws of nature are discussed. A selection of original papers is reprinted.

At a fundamental level, the interaction of quarks with gluon fields lies at the heart of our understanding of the strong nuclear force. Experimentally, however, we only observe physical hadrons such as protons and pions. This book explores the fascinating physics involved in the path between these contrasting pictures of the world. Along the way, the book discusses symmetries, which play a crucial role in understanding the parameters of the theory, and details of the spectrum of physical particles.This would be the first book to elaborate on the detailed connections between confinement and chiral symmetry, with an emphasis on a unified treatment of the non-perturbative nature of these phenomena. As such, it should be a valuable title on any particle theorist's bookshelf, containing extensive pedagogical material for scientists at the graduate level and above.

According to the current view, the basic building blocks of matter are quarks and leptons, which interact with one another through the intermediaries of Yang-Mills gauge fields. The forms of interactions are determined by the algebraic structure of certain internal symmetry groups. The strong interactions are associated with the group SU(2) x U(1). This book is a concise introduction to the physical motivation behind these ideas and precise mathematical formulation thereof. The goal of this book is to explain why and how the mathematical formalism helps us to understand the relevant observed phenomena. This book serves as a text for a one-semester course beyond quantum field theory. The material was taken in part from such a course offered by the author at MIT. Request Inspection Copy

The theoretical understanding of elementary particle interactions has under gone a revolutionary change during the past one and a half decades. The spontaneously broken gauge theories, which in the 1970s emerged as a prime candidate for the description of electro-weak (as weIl as strong) interactions, have been confirmed by the discovery of neutral weak currents as weIl as the w- and Z-bosons. We now have a field theory of electro-weak interactions at energy scales below 100 GeV-the Glashow-Weinberg-Salam theory. It is a renormalizable theory which enables us to do calculations without en countering unnecessary divergences. The burning question now is: Wh at lies ahead at the next level of unification? As we head into the era of supercolliders and ultrahigh energy machines to answer this question, many ap, pealing possi bilities exist: left-right symmetry, technicolor, compositeness, grand unifica ti on, supersymmetry, supergravity, Kaluza-Klein models, and most recently superstrings that even unify gravity along with other interactions. Experi ments will decide if any one or any combination of these is to be relevant in the description of physics at the higher energies. As an outcome of our con fidence in the possible scenerios for elementary particle physics, we have seen our understanding of the early uni verse improve significantly.

Ch. 1. Ingredients of the standard model. 1.1. Strong interaction - QCD. 1.2. Electroweak theory. 1.3. CKM mass matrix -- ch. 2. Symmetries and wave functions. 2.1. Why is symmetry important? 2.2. Symmetry current. 2.3. SU(2). 2.4. SU(3). 2.5. Multi-particle states. 2.6. Product-states. 2.7. Quark model wave functions -- ch. 3. Chiral symmetry. 3.1. Lorentz group and chiral fermions. 3.2. Chiral group. 3.3. Spontaneous breaking of chiral symmetry -- ch. 4. The sigma model. 4.1. Linear sigma model. 4.2. Non-linear sigma model. 4.3. Fermion field -- ch. 5. Chiral bag model. 5.1. The MIT bag model. 5.2. The little bag model. 5.3. The Skyrme model. 5.4. The chiral bag model. 5.5. Chiral casimir effects. 5.6. The edgehog solution -- ch. 6. Nucleon properties. 6.1. Semiclassical method. 6.2. Isospin rotation of the hedgehog solution. 6.3. Axial properties. 6.4. Non-rigid quantization of the skyrmion. 6.5. Electromagnetic properties. 6.6. Chiral bag with vector mesons -- ch. 7. Large-Nc baryons. 7.1. Introduction. 7.2. General counting rules. 7.3. Counting rules for solitons. 7.4. Large-Nc algebra for baryons. 7.5. Finite Nc. 7.6. Other representations and gA -- ch. 8. Excited baryons. 8.1. Systematics in baryon masses. 8.2. Quarks in a deformed oscillator potential. 8.3. Electromagnetic transitions.

Many courses on modern quantum field theory focus on the formulation and application of field theory, leaving topics related to symmetry underdeveloped. This leads to students often having an incomplete understanding of symmetries. Filling this gap, Symmetries and Symmetry Breaking in Field Theory sheds light on various aspects of symmetry in field theory. The book presents a broad selection of important topics, including constraint theory, generalized Pauli–Villars regularization, the measure approach to anomalies, zeta function regularization, and anomalous gauge theories. The author explains how some classical symmetries are broken by anomalies and how other symmetries of the theory are spontaneously broken. He discusses all of the ideas in as simple a way as possible.