Download or read book Nucleon Resonance Excitation with CLAS written by R. De Vita and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of the baryon spectrum is a fundamental part of the scientific program in Hall B at Jefferson Laboratory. The so called N* program indeed concerns the measurement of the electromagnetic production of exclusive hadronic final states, with the purpose of extracting information on baryon excited states. CLAS, the CEBAF Large Acceptance Spectrometer, is explicitly designed for conducting a broad experimental program in hadronic physics, using the continuous electron beam provided by the laboratory. An overview of the most recent results is presented.
Download or read book Electroexcitation of Nucleon Resonances from CLAS Data on Single Pion Electroproduction written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present results on the electroexcitation of the low mass resonances Delta(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of JLab-CLAS data on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for pion electroproduction off the proton. The data were analysed using two conceptually different approaches, fixed-t dispersion relations and a unitary isobar model, allowing us to draw conclusions on the model sensitivity of the obtained electrocoupling amplitudes. The amplitudes for the Delta(1232)P33} show the importance of a meson-cloud contribution to quantitatively explain the magnetic dipole strength, as well as the electric and scalar quadrupole transitions. They do not show any tendency of approaching the pQCD regime for Q26 GeV2. For the Roper resonance, N(1440)P11, the data provide strong evidence for this state as a predominantly radial excitation of a 3-quark ground state. Measured in pion electroproduction, the transverse helicity amplitude for the N(1535)S11 allowed us to obtain the branching ratios of this state to the piN and etaN channels via comparison to the results extracted from eta electroproduction. The extensive CLAS data also enabled the extraction of the gamma*p - N(1520)D13 and N(1535)S11 longitudinal helicity amplitudes with good precision.
Download or read book Excited Nucleons and Hadronic Structure written by V. Burkert and published by World Scientific. This book was released on 2001 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Recent Results on the Nucleon Resonance Spectrum and Structure from the CLAS Detector written by and published by . This book was released on 2016 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CLAS detector at Jefferson Lab has provided the dominant part of all available worldwide data on exclusive meson electroproduction off protons in the resonance region. New results on the $\gamma_{v}pN^*$ transition amplitudes (electrocouplings) are available from analyses of the CLAS data and will be presented. Their impact on understanding of hadron structure will be discussed emphasizing the credible access to the dressed quark mass function that has been achieved for the first time by a combined analysis of the experimental results on the electromagnetic nucleon elastic and $N \rightarrow N^*$ transition form factors. We will also discuss further convincing evidences for a new baryon state $N^{\, '}(1720)3/2^+$ found in a combined analysis of charged double pion photo- and electroproduction cross sections off the protons.
Download or read book NSTAR 2001 written by D. Drechsel and published by World Scientific. This book was released on 2001 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positive pion photoproduction and compton scattering at GRAAL / V. Kouznetsov for the GRAAL collaboration -- Virtual compton scattering and pion electroproduction in the nucleon resonance region / G. Laveissiere for the Jefferson Lab Hall A collaboration -- Single spin beam asymmetry measurements from single [symbol] electroproduction in the [symbol](1232) resonance region / K. Joo -- The new crystal ball experimental program / W. J. Briscoe -- Observation of [symbol]-mesic nuclei in photoreactions: Results and perspectives / G. A. Sokol, A. I. L'vov, L. N. Pavlyuchenko -- Baryon spectroscopy: Experiments at PNPI / I. Lopatin -- Measurement of the cross section asymmetry in deuteron photodisintegration by linearly polarized photons in the energy range E[symbol] = 0.8 - 1.6 GeV / A. Sirunian ... [et al.] -- Nucleon resonances in lattice QCD / F. X. Lee -- Lattice study of nucleon properties with domain wall fermions / S. Sasaki -- Quark-hadron duality: Resonances and the onset of scaling / W. Melnitchouk -- Generalized GDH sum rule and spin-dependent electroproduction in the resonance region / J. P. Chen for the Jefferson Lab E94-010 collaboration -- Double polarization measurements using the CLAS at JLab / R. C. Minehart for the CLAS collaboration -- The helicity dependent excitation spectrum of the nucleon and the GDH sum rule / A. Thomas for the GDH- and A2-collaborations -- Static magnetic moment of the [symbol](1232) / M. Kotulla for the TAPS and AS collaborations -- Meson photoproduction at GRAAL / A. D'Angelo ... [et al.] -- Maximum likelihood techniques for PWA of 2-pion photoproduction / J. P. Cummings -- [symbol] electroproduction with CLAS / J. A. Mueller -- Kaon electroproduction and [symbol] polarization observables measured with CLAS / B. Raue for the CLAS collaboration -- Recent results on kaon photoproduction at SAPHIR in the reactions [symbols] and [symbols] / K.-H. Glander for the SAPHIR collaboration -- Vector meson decay of baryon resonances / U. Mosel, M. Post -- Higher and missing resonances in [symbol] photoproduction / Y. Oh, A. I. Titov, T.-S. H. Lee -- Photoproduction of baryon resonances, first data from the CB-ELSA experiment / U. Thoma for the CB-ELSA collaboration -- Laser-electron photon project at SPring-8 / T. Nakano -- The baryon resonance program at BES / B.S. Zou for the BES collaboration -- Flavor symmetry studies with new hyperon data from the crystal ball / B. M. K. Nefkens ... [et al.] for the Crystal Ball collaboration -- Higher resonances and the example of two pion electroproduction with the CLAS detector at Jefferson Lab / M. Ripani for the CLAS collaboration -- Nucleon resonances and mesons in nuclei / V. Metag -- Excitation of nucleon resonances / V. D. Burkert -- Summary of the partial wave analysis group of BRAG: Multipole analysis of a benchmark data set for pion photoproduction / R. A. Arndt ... [et al.].
Download or read book Nstar 2005 Proceedings Of The Workshop On The Physics Of Excited Nucleons written by Simon Capstick and published by World Scientific. This book was released on 2006-06-08 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Excited Nucleons And Hadron Structure Proceedings Of The Nstar 2000 Conference written by Volker Burkert and published by World Scientific. This book was released on 2001-02-28 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The CLAS Excited Baryon Program at Jefferson Laboratory written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleons are complex systems of confined quarks and exhibit characteristic spectra of excited states. Highly excited nucleon states are sensitive to details of quark confinement which is poorly understood within Quantum Chromodynamics (QCD), the fundamental theory of strong interactions. Thus, measurements of excited states and the corresponding determination of their properties are needed to come to a better understanding of how confinement works in nucleons. However, the excited states of the nucleon cannot simply be inferred from cleanly separated spectral lines. Quite the contrary, a spectral analysis in nucleon resonance physics is challenging because of the fact that the resonances are broadly overlapping states which decay into a multitude of final states involving mesons and baryons. To provide a consistent and complete picture of an individual nucleon resonance, the various possible production and decay channels must be treated in a multi-channel framework that permits separat.
Download or read book Nstar 2004 Proceedings Of The Workshop On The Physics Of Excited Nucleons written by Viatcheslav Kouznetsov and published by World Scientific. This book was released on 2004-11-23 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Court Rolls of the Borough of Colchester written by Colchester(Borough.). Council and published by . This book was released on 1921 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NSTAR 2005 written by Simon Capstick and published by World Scientific. This book was released on 2006 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Evidence for New Nucleon Resonances from Electromagnetic Meson Production written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of nucleon resonances in electromagnetic meson production with the CLAS detector is discussed. The electromagnetic interaction is complementary to pion scattering in the exploration of the nucleon excitation spectrum. Higher mass states often decouple from the N? channel and are not seen in? N -->? N. Photoproduction of mesons, such as K?,? p and?' p may be more sensitive to many of these states. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as po- larized targets and the measurement of recoil polarization, are the tools needed for a comprehensive nucleon resonance program. Some of the recently published high statistics data sets had significant impact on further clarifying the nucleon excitation spectrum.
Download or read book Probing the Structure of Nucleons in the Resonance Region with CLAS at Jefferson Lab written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The physics of electromagnetic excitation of nucleon resonances and of their relevance in nucleon structure studies are discussed. Preliminary data from the CLAS detector on the N-Delta(1232) transition multipoles, the helicity amplitudes of the N*(1535), and the search for so-called ''missing resonances'' at Jefferson Lab are presented.
Download or read book Nucleon Resonance Studies in Phenomenological Analysis of the CLAS written by Volker Burkert and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: First comprehensive data on the evolution of nucleon resonance photocouplings with photon virtuality Q{sup 2} are presented for excited proton states in the mass range from 1.4 to 2.0 GeV.
Download or read book Nstar 2002 Proceedings Of The Workshop On The Physics Of Excited Nucleons written by Steven A Dytman and published by World Scientific. This book was released on 2003-07-07 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers recent advances in the physics of nucleon resonances, including new experimental results from laboratories in the USA, Europe, and Asia, and new developments in effective field theories, quark models, and lattice gauge theory.
Download or read book Transition Form Factor from CLAS written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The excitation of nucleon resonances in electromagnetic interaction has long been studied. The study of resonances helps us to understand the long- and short- range structures of the nucleon and its excited states in terms of quark confinement. While the existing data of the low-lying resonances are consistent with the well-studied SU(6) circle times operator O(3) constituent quark model classification, many open questions still remain. Exclusive electro-production is one of the best ways to investigate nucleon resonances. The exclusive electro-production process View the MathML source was measured in the photon virtuality range Q2 = 1.7 â 4.5 GeV2 and the invariant mass range for the n?+ system of W = 1.15 â 1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive?+ production from protons with nearly full coverage in the azimuthal and polar angles of the n?+ center-of-mass system. The n?+ channel has particular sensitivity t.
Download or read book Nucleon Resonance Electrocouplings from the CLAS Data on Exclusive Meson Electroproduction Off Protons written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ?{Sub v}NN* transition helicity amplitudes (electrocouplings) of several prominent excited proton states are determined for the first time in independent analyses of?n,?°p, and?+?−p electroproduction off protons. Consistent results on resonance electrocouplings obtained from major meson electroproduction channels offer an evidence for reliable extraction of these fundamental quantities. Analysis of?+?−p electroproduction has extended considerably information on electrocouplings of high lying N* states, which decay preferentially to the N?? final states.
