Excited Nucleons And Hadronic Structure

The conference NSTAR 2000 was part of a series of conferences and workshops that began in New York in 1988. Since then, the field of excited nucleons and hadron structure has developed enormously, and the scope has broadened. Most significantly, new experimental facilities have come into operation, allowing precise measurements of resonance couplings and transition form factors. The search for “missing” quark model states and gluonic excitations in complex hadronic channels is now possible.On the theory side, new and promising developments have emerged: quark models with meson degrees of freedom, hybrid baryon models, and studies of baryons in the limit of many colors. For the first time, lattice QCD has been employed to calculate masses of excited nucleons. Nucleon resonances are now recognized as providing significant contributions to the nucleon spin sum rules, as well as the Gerasimov-Drell-Hearn and Bjorken integrals, at finite momentum transfer.

The conference NSTAR 2000 was part of a series of conferences and workshops that began in New York in 1988. Since then, the field of excited nucleons and hadron structure has developed enormously, and the scope has broadened. Most significantly, new experimental facilities have come into operation, allowing precise measurements of resonance couplings and transition form factors. The search for ?missing? quark model states and gluonic excitations in complex hadronic channels is now possible.On the theory side, new and promising developments have emerged: quark models with meson degrees of freedom, hybrid baryon models, and studies of baryons in the limit of many colors. For the first time, lattice QCD has been employed to calculate masses of excited nucleons. Nucleon resonances are now recognized as providing significant contributions to the nucleon spin sum rules, as well as the Gerasimov-Drell-Hearn and Bjorken integrals, at finite momentum transfer.

This volume brings together experts on the quark-gluon structure of matter as it applies to nucleon resonance physics. The contributions discuss the latest findings in areas such as meson production via electromagnetic and hadronic reactions, baryon resonance structure in chiral and lattice QCD approaches, and the extraction of resonance parameters from coupled-channels analysis of data. Contents: MAID Analysis Technique (L Tiator); Results from the GDH Experiment at Mainz and Bonn (A Braghieri); The Crystal Ball at MAMI (D Watts); Dynamically Generated Baryon Resonances (M Lutz); Progress Report for a New Karlsruhe-Helsinki Type Pion-Nucleon Partial Wave Analysis (S Watson); A Genetic Algorithm Analysis of N * Resonances (D G Ireland); Eta Photoproduction of the Neutron at GRAAL (V Kuznetsov); The Problem of Exotic States: View from Complex Angular Momenta (Ya Azimov); Excited Baryons in the 1/ N c Expansion (N Matagne); and other papers. Readership: Researchers in nuclear, high-energy and particle physics.

The 13 lectures from a course in sub-atomic systems for graduate and post-doctorate physics students, held in Dronton, The Netherlands, in August 1993. They address the hadronic structure starting at low energies with meson production and nucleon resonance excitation in lepton and hadron scattering

This book covers recent advances in the field of nucleon resonances presented at the IX International Workshop on the Physics of Excited Baryons, NSTAR2004. A complete overview of the most recent experimental results obtained worldwide on baryon spectroscopy is presented together with theoretical progress on related topics ranging from resonance parameters extraction to lattice-QCD calculations through effective field theory. Of particular interest, a large part of the book is devoted to exotic states with quantum numbers of pentaquarks, whose recent discovery represents a new chapter in hadronic physics. The proceedings have been selected for coverage in: • Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings) • CC Proceedings — Engineering & Physical Sciences Contents: Search for Pentaquark States with CLAS at Jefferson Lab (V Burkert et al.)The Status of Pentaquark Spectroscopy on the Lattice (T G Kovàcs et al.)Pentaquark Spectra in the Diquark Picture (C Semay et al.)CLAS Results from the First and Second Resonance Regions (L C Smith et al.)Dynamical Baryon Resonances from Chiral Unitarity (A Ramos et al.)Generalized Parton Distributions in the Light-Front Constituant Quark Model (S Simula)Compton Scattering of Polarized Photons on the Proton at GRAAL (O Bartalini et al.)New Evidence for the Breathing Mode of the Nucleon from High-Energy Proton-Proton Scattering (H-P Morsch & P Zupranski)Strong Decay of N and Δ Resonances in the Point-Form Formalism (T Melde et al.)Baryon Form Factors in the Three Forms of Relativistic Kinematics (B Juliá-Díaz et al.)and other papers Readership: Researchers in the field of nucleon resonances. Keywords:Nucleon Resonances;Baryon Spectroscopy;Exotic States;Pentaquarks;Meson Photo- and Hadroproduction;Coupled-Channel Calculations;Partial Wave Analysis;Lattice-QCD;Chiral and QCD-Inspired Models

The study of N∗s can provide us with critical insights into the nature of QCD in the confinement domain. The keys to progress in this domain are the identification of its important degrees of freedom and the effective forces between them. The nucleon is the simplest system in which the nonabelian character of QCD is manifest. There are Nc quarks in a baryon because there are Nc colors, and as a consequence Gell-Mann and Zweig were forced to introduce the quarks in order to describe the octet and decuplet baryons.This volume gives a status report on the recent experimental and theoretical results in the field of nucleon resonance physics. A wealth of new high precision data was presented from facilities around the world, such as BES, BNL, ELSA, GRAAL, JLab, MAMI, MIT/Bates, SPring8, and Yerevan. Particular emphasis was laid on polarization degrees of freedom and large acceptance detectors as precision tools for studying small but important transition amplitudes, and the helicity (spin) structure of the nucleon. There were new results describing the nucleon resonance structure on the basis of quantum chromodynamics, either directly in terms of quarks and gluons by means of lattice gauge theory, or in terms of hadrons in the framework of chiral field theories. A status report on duality showed the surprising connections between the physics of the low energy nucleon resonance region and the realm of quark structure functions in deep inelastic scattering. Finally, this volume contains a summary report of the BRAG workshop, devoted to the analysis of baryon resonances.

This volume brings together experts on the quark-gluon structure of matter as it applies to nucleon resonance physics. The contributions discuss the latest findings in areas such as meson production via electromagnetic and hadronic reactions, baryon resonance structure in chiral and lattice QCD approaches, and the extraction of resonance parameters from coupled-channels analysis of data.