Download or read book Production of Resonances Using CLAS at Jefferson Lab written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of hadronic resonances produced in photoproduction reactions at Jefferson Lab are shown and discussed. Emphasis is placed on the production of the excited hyperon states Sigma(1385), Lambda(1405), and Lambda(1520). Some future prospects for the upcoming Jefferson Lab 12 GeV era are given, where the CLAS12 and GlueX detectors will see unprecedented amounts of data using electromagnetic probes and further our knowledge of hadronic resonances.
Download or read book Resonance Production Through the Two Neutral Pion Channel written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have obtained data for the[gamma]p[yields][pi][sup 0][pi][sup 0] reaction with the CLAS at Jefferson Lab for photon energies 0.4
Download or read book Strangeness Production and Other Recent Results from Hall B at Jefferson Lab written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results using the CLAS detector at Jefferson Lab are discussed. We emphasize strangeness photo- and electro-production in the baryon resonance region between W= 1.6 and 2.3 GeV, where indications of s-channel structure are suggestive of high-mass baryon resonances coupling to kaons and hyperons in the final state. Other CLAS results, for the E 1+ /M 1+ transition form factor at the first[Delta]-resonance, two-pion electroproduction, and[eta] photoproduction are also briefly mentioned.
Download or read book Electromagnetic Production of Hyperon Resonances written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. Examples of physics results are: evidence for isospin interference in the decay of the [Lambda](1405) resonance; a strong suggestion of meson cloud effects in the structure of the [Sigma](1385) resonance; data from K* photoproduction that will test the existence of the purported K0(800)$ meson. Properties of other hyperon resonances will also be studied in the near future.
Download or read book Strangeness Production and Other Recent Results from Hall B at Jefferson Lab written by R. A. Schumacher and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results using the CLAS detector at Jefferson Lab are discussed. We emphasize strangeness photo- and electro-production in the baryon resonance region between W = 1.6 and 2.3 GeV, where indications of s-channel structure are suggestive of high-mass baryon resonances coupling to kaons and hyperons in the final state. Other CLAS results, for the E 1 + /M 1 + transition form factor at the first {Delta}-resonance, two-pion electroproduction, and {eta} photoproduction are also briefly mentioned.
Download or read book Photoproduction of and 0 Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2002 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, ? p → K+ ? and ? p → K+ ?0 , have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the ? p → K+ ? reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately ? = 100 MeV. In both ? p → K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for ? p → K+ ? shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of ? p → K+ ?0 at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Refereed and selected contributions from International Conference on Quark Nuclear Physics written by Charlotte Elster and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the refereed and selected contributions from the International Conference on Quark Nuclear Physics (QNP2002), held from 9 to 14 June 2002 in Jülich, Germany.
Download or read book Exclusive pi Electro production from the Neutron in the Resonance Region written by Jixie Zhang and published by . This book was released on 2010 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single Pi0 Electro production in the Resonance Region with CLAS written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the analysis status of single [pi]0 electroproduction in the resonance region to study the electromagnetic excitation of the nucleon resonances. The study is aimed at understanding of the internal structure and dynamics of the nucleon. The experiment was performed using an unpolarized cryogenic hydrogen target and 2.0 and 5.8 GeV polarized electron beam during the e1e and e1-6 run periods with CLAS at Jefferson Lab. The new measurements will produce a data base with high statistics and large kinematic coverage for the hadronic invariant mass (W) up to 2.0 GeV in the momentum transfer (Q2) range of 0.3--6.0 GeV2. Preliminary results will be presented and compared with the various model calculations.
Download or read book Photoproduction Of Lambda And Sigma sup 0 Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, [gamma] p[yields] K[sup+][Lambda] and[gamma] p[yields] K[sup+][Sigma][sup 0], have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the[gamma] p[yields] K[sup+][Lambda] reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately[Gamma]= 100 MeV. In both[gamma] p[yields] K[sup+] Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for[gamma] p[yields] K[sup+][Lambda] shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of[gamma] p[yields] K[sup+][Sigma][sup 0] at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Search for N Resonances in Double Polarization Experiments Using CLAS written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: At medium energies where the strong coupling constant is very large and perturbative methods can no longer be applied, the nature of confinement remains one of the key challenges in our present understanding of QCD. A necessary step is undoubtedly to identify the relevant degrees of freedom in this energy regime and the effective forces between them. Thus, a precise knowledge of the spectrum of baryon resonances and their properties is needed. A large number of states has been found in different analyses. However, only a few of them are well established and confirmed by different experiments. It has been shown that particular resonances have large effects on polarization observables. At Jefferson Laboratory, a major program has been proposed to perform a large set of photoproduction experiments using linearly- and circularly-polarized tagged photon beams as well as longitudinally and transversely-polarized targets. In double-pion production, a major obstacle in the determination of the couplings of baryon resonances are the considerable contributions from non-resonant mechanisms, m this case, polarization observables, which are sensitive to very small resonance contributions, will be helpful in the evaluation of N* properties.
Download or read book Photoproduction of Lambda and Sigma Hyperons Off Protons in the Nucleon Resonance Region Using CLAS at Jefferson Lab written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross section and hyperon recoil polarizations of the photoproduction of the ground state hyperons, [gamma] p 2!K [Lambda] and [gamma] p 2!K [Sigma]°, have been measured with the CLAS at Jefferson Lab up to a photon energy in the lab of 2.325 GeV. The results for both channels show significantly larger cross section in the middle to forward angles than have been observed previously by the SAPHIR Collaboration. Both reactions show significantly more backward peaking in the angular distributions than has previously been possible to observe. The backward peaking hints that hyperon resonances in the u-channel play a significant role in the production mechanism. In addition, in the [gamma] p 2!K+ [Lambda] reaction, a previously unobserved bump in the cross section was observed at forward angles, centered on a W of 1.95 GeV with a width of approximately [Gamma] = 100 MeV. In both [gamma] p 2!K+ Y reactions the recoil polarization in the forward direction seems reasonably well reproduced by t-channel interferences in a Regge model calculation as well as hadrodynamic models that include kaon resonances in the t-channel. The recoil polarization for [gamma] p 2!K+ [Lambda] shows a significant enhancement around a W of 1.9 GeV in the backward angles, which is a sign of resonance activity in this vicinity. The polarization of [gamma] p 2!K+ [Sigma]° at backward angles is, in contrast, less pronounced and mostly consistent with zero.
Download or read book Nstar2007 written by Hans W. Hammer and published by Springer Science & Business Media. This book was released on 2009-04-23 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: c Societ` a Italiana di Fisica / Springer-Verlag 2008 The 11th Workshop on The Physics of Excited Nucleons, NSTAR 2007, was held at the University of Bonn, Germany,fromSeptember5–8,2007.ItwasthelatestofaseriesofsuccessfulconferencesattheRensselaerPolytechnic Institute (1988), Florida State University (1994 and 2005), Je?erson Lab (1995 and 2000), INT Seattle (1996), GWU ? Washington (1997), ECT Trento (1998), Mainz (2001), Pittsburgh (2002) and the LPSC Grenoble (2004). A Baryon Resonance Analysis Group (BRAG) meeting immediately before the workshop focused especially on the physical meaning of bare and dressed scattering matrix singularities. A focus workshop on? photoproduction rounded o? the NSTAR 2007. The goal of NSTAR 2007 was to bring together experts on all areas of physics relevant to baryon spectroscopy, both in experiment and theory. Latest results were presented in 30 plenary talks and 34 parallel contributions, the proceedings of which are collected in this volume. The workshop was attended by 123 scientists of 41 universities and laboratories from 16 countries. Exciting new high-precision data were shown from facilities in Asia, the US and Europe, e.g. BES, BNL, COSY, ELSA, GRAAL, JLab, MAMI and LEPS. Large-acceptance detectors provide complete angular distributions in many reaction channels. Particular emphasis is put on the measurement of single and double polarisation observables such that many new polarization measurements can be expected in forthcoming meetings.
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 N Physics and Nonperturbative Quantum Chromodynamics written by Silvano Simula and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Workshop N* Physics and non-perturbative QeD was held at the Eu ropean Center for Theoretical Studies and Related Areas (ECT*) in Trento, Italy, during May 18-29, 1998. Previous workshops of the series on N* Physics took place at the Florida State University (1994), at CEBAF (1995), at the Institute for Nuclear Theory in Seattle (1996) and at the George Washington University (1997). The Workshop was devoted to a summary of recent experimental and the oretical research on N* phsyics and special emphasis was given to the infor mation that photo-and electro-production of nucleon resonances can provide on the non-perturbative regime of Quantum Chromodynamics. The idea was to stimulate discussions among experimentalists and theoreticians in order to pursue the interpretation of the huge amount of forthcoming data from several laboratories in the world. It was therefore decided to have both experimental and theoretical lectures on the main topics, like ,among the others, single and double pion production, TJ-and K-meson production, the GDH sum rule, the spin of the proton, etc. Thanks to the unusual two-week extension of the Work shop, the allotted time for the lectures was extended up to one hour in order to allow the invited lecturers to give a detailed presentation of their topics. Fi nally, various short contributions were selected to sharpen the discussion about selected items.
Download or read book Perspectives in Hadronic Physics written by Sigfrido Boffi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the invited and contributed papers presented at the Fourth International Conference on Perspectives in Hadronic Physics and sent to the Editors within the deadline. The Conference was held at the Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy, from May 12th to 16th, 2003, and was attended by about 100 scientists from 20 countries. The series ofConferences on Perspectives on Hadronic Physics takes place every two years since 1997 and follows the seven Workshops on Perspectives in Nuclear Physics at Intermediate Energies, organized every two years at ICTP since 1983. The aim of these Conferences is to discuss the status-of-the-art concerning the experimental and theoretical investigations of hadronic systems, from nucleons to nuclei and dense nuclear matter, in terms of the relevant underlying degrees of freedom. For such a reason the Fourth Conference has been focused on those experimental and theoretical topics which have been in the last few years the object of intensive investigations, viz. the various approaches employed to describe the structure of hadrons in terms of QCD and QCD inspired models, the recent developments in the treatment of the properties and propagations of hadronic states in the medium, the relevant progress done in the solution of the few- and many- hadron problems, the recent results in the experimental investigation of dense hadronic matter and, last but not least, the physics programs of existing Laboratories and the suggested projects for new Facilities.
Download or read book Meson Production and Baryon Resonances at CLAS written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I give a brief overview of the exploration of baryon properties in meson photo- and electroproduction. These processes provide ample information for the study of electromagnetic couplings of baryon resonances and to search for states, yet to be discovered. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as polarized targets and the measurement of recoil polarization, provide the tools for a comprehensive nucleon resonance program. I briefly present the status of this program, prospects for the next few years, and plans for the Jefferson Lab 12 GeV upgrade.
