Quark Confinement And The Hadron Spectrum Ii

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.

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.

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, SchwingerOCoDyson approach and lattice QCD results). The fourth section deals with the deconfinement mechanism and quarkOCogluon 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."

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 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 interactions with theoretical and experimental highlights included. It is divided into five sections. The first section is devoted to the investigations into the QCD Vacuum 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.