From Quarks To Pions Chiral Symmetry And Confinement

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.

Filling the gap in the literature on low-energy quark models, The Quark Confinement Model of Hadrons investigates confinement effects in the low-energy regions of particle physics using the methods of nonlocal quantum field theory. It also elucidates their role in describing microscopic quantities that characterize hadron-hadron interactions. The authors present a quark confinement model to describe the low-energy physics of light hadrons. Hadrons are treated as collective colorless excitations of quark-gluon interactions while the quark confinement is to be provided by averaging over gluon backgrounds. The model is shown to reproduce the low-energy relations of chiral theory in the case of null momenta and, in addition, allow the researcher to obtain more sophisticated hadron characteristics, such as slope parameters and form factors. Presenting a unified view on a number of low-energy phenomena, The Quark Confinement Model of Hadrons enables an understanding of problems related to the treatment of large distances within quantum chromodynamics.

Quantum chromodynamics is generally accepted to be the quantum field theory which describes the strong interactions in elementary particle physics. However, the question of the mechanism responsible for the “confinement” of the color degrees of freedom of quarks and gluons into hadrons still ranks as one of the most interesting open problems in physics. This proceedings volume summarizes the state of the art in this area of research. Mathematically inclined readers will find the articles based on monopoles, vortices, and topology most interesting. Meanwhile, lattice calculations can be performed for many important physical quantities. Their results can be used as guidelines for developing models of quark confinement. These models are indispensable for theoretical physicists performing calculations with the Bethe–Salpeter equation, Dyson–Schwinger equations, effective Hamiltonians, and potential models. The cross-fertilization of all these subfields of research becomes evident from the articles in this book. A few experimental papers are also included. Contents:Contemporary Applications of Dyson–Schwinger Equations (M B Hecht et al.)Strangeness Production Using Electrons (O K Baker)Glueballs, Hybrid and Exotic Mesons and String Breaking (C Michael)The Gluon Condensate from Gauge Invariant Vortex Vacuum Texture (K Langfeld)Quark Confinement in the Analytic Approach to QCD (A V Nesterenko)Confinement Picture in Dual Formulation of Lattice Gauge Models (O Borisenko & M Faber)Hamiltonian Lattice Gauge Theory (N E Ligterink)Electromagnetic Properties of Light Nucleon Resonances in a Chiral Constituent Quark Model (R F Wagenbrunn et al.)Relationship of Pionium Lifetime with Pion Scattering Lengths in Generalized Chiral Perturbation Theory (H Sazdjian)The Mass of the b Quark from Lattice NRQCD (S Collins)Weak Form Factors for Heavy Meson Decays (D Melikhov & B Stech)Instantaneous Bethe-Salpeter Equation: (Semi-) Analytical Solution (W Lucha et al.)QCD Sum Rules at Finite Temperature and Density (S Mallik)Mass of the Bottom Quark (W Lucha & F F Schöberl)and other papers Readership: Researchers, academics and graduate students in high energy physics. Keywords:

The 20-year-old problem of the confinement and the resulting spectrum of the bound states is central to quantum chromodynamics (QCD). Many approaches have been tried starting from different points of view: the potential theory, the Bethe-Salpeter equation, string and flux tube models, bag models, vacuum structure, current algebra, lattice theory, and numerical simulations. Phenomenological assumptions and first-principle theoretical results or indications have been combined. Many partial successes have been attained, but a unified and comprehensive treatment is still lacking.In recent years, new attention has been given to the problem, both in terms of theoretical developments and for the purpose of evaluating the spectrum and other properties of the particles. In particular, attention has been focussed on areas like numerical simulations, the derivation of the potential, the use of the Bethe-Salpeter equation, the connection between the potential and the chiral symmetry approach.This workshop was an opportunity for a synthesis and a comparison of the different points of view.

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 problem of quark confinement is one of the classic unsolved problems of particle physics and is fundamental to our understanding of the physics of the strong interaction and the behaviour of non-Abelian gauge theories in general. The confinement problem is also are area in which concepts from topology and techniques of computational physics both find important applications. This volume contains a snapshot of current research in this field as of January 2002. Particular emphasis is placed on the role of topological field configurations such as centre vortices and monopoles in proposed confinement mechanisms. Other topics covered include colour superconductivity, instantons and chiral symmetry breaking, matrix models and the construction of chiral gauge theories. Readership: Research scientists and graduate students of high energy physics and nuclear physics.

The confinement mechanism of the quarks in QCD is one of the most challenging and open problems in physics. Confinement is a nonperturbative phenomenon, and a definite way to handle it has not yet been found in field theory. There are lattice calculations that can produce the low-lying states of the spectrum and ?measure? many important physical quantities, but nevertheless the development of analytical techniques is of extreme importance for understanding the physics involved in confinement. In this respect it is important to test the results obtained directly from the theory (Bethe-Salpeter kernel, effective Hamiltonians, quark potential, etc.) on the spectrum, form factors and decays of bound states of quarks and gluons, and to relate them to the results of lattice theory.In this book, the question of the confinement mechanism is addressed; explanations in terms of monopoles, instantons and dyons are reviewed and the connection with duality is discussed.

This book provides an update on our understanding of strong interaction, with theoretical and experimental highlights included. It is divided into five sections. The first section is devoted to the investigations into and the latest results on the mechanism of quark confinement. The second and third sections focus respectively on light and heavy quarks (effective field theories, Schwinger–Dyson approach and lattice QCD results). The fourth section deals with the deconfinement mechanism and quark–gluon plasma formation signals. The last section presents highlights of experiments, new physics beyond QCD, and nonperturbative approaches in other theories (strings and SUSY) that may be useful in QCD. Contents:Vortices, Confinement and Higgs Fields (R Bertle & M Faber)Hadronic Signature of Quark–Gluon Plasma (J Rafelski & J Letessier)Topology of Center Vortices (H Reinhardt)The Nonperturbative Quark-Gluon Vertex (J Skullerud et al.)Equivalence in Minkowski and Euclidean Field Theories (K M Maung et al.)Criterium for the Index Theorem on the Lattice (P Bicudo)Isospin Breaking in the Goldberger–Treiman Discrepancies (J L Goity & J Saez)Quantum Field Theory Approach to the Vacuum Replica in QCD (A V Nefediev & J E F T Ribeiro)Charm and Bottom Quark Masses from QCD Moment Sum Rules (M Eidemüller)Dilepton Production in Heavy-Ion Collisions: A Probe of Deconfinement (E Scomparin)Deuteron Photodisintegration at High Energy (F Ronchetti)Semianalytical Bounds on Spinless–Salpeter Energy Levels (R L Hall et al.)String Breaking and Monopoles in the 3D Abelian Higgs Model (M N Chernodub et al.)and other papers Readership: Researchers in high-energy, particle, theoretical, accelerator and experimental physics. Keywords:Gauge Field Theories;Models beyond the Standard Model;Chiral Symmetries;Perturbative and Nonperturbative QCD;Deconfinement;Hadrons