Strangeness Physics with CLAS at Jefferson Lab PDF Download

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Languages : en
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A brief overview of strangeness physics with the CLAS detector at JLab is given, mainly covering the domain of nucleon resonances. Several excited states predicted by the symmetric constituent quark model may have signi cant couplings to the K+ or K0 channels. I will discuss data that are relevant in the search for such states in the strangeness channel, and give an outlook on the future prospects of the N* program at JLab with electromagnetic probes.

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Languages : en
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An extensive program of strange particle production off the nucleon is currently underway with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Laboratory. This talk will emphasize strangeness electroproduction in the baryon resonance region between W=1.6 and 2.4 GeV, where indications of s-channel structure are suggestive of high-mass baryon resonances coupling to kaons and hyperons in the final state. Precision measurements of cross sections and polarization observables are being carried out with highly polarized electron and real photon beams at energies up to 6 GeV. The near-term and longer-term future of this program will also be discussed.

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Languages : en
Pages : 7

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A very brief overview is presented of varied strangeness-physics studies that have been conducted with the CLAS system in the era of 6 GeV beam at Jefferson Lab. A full bibliography of articles related to open strangeness production is given, together with some physics context for each work. One natural place where these studies could be continued, using a K L beam and the GlueX detector, is in the further investigation of the [Lambda](1405) baryon. The line shapes and cross sections of this state were found, using photoproduction at CLAS, to differ markedly in the three possible [Sigma][pi] final states. The analogous strong-interaction reactions using a K L beam could further bring this phenomenon into focus. 1. The CLAS program ran from 1998 to 2012, during the time when the maximum Jefferson Lab beam energy was 6 GeV. An important thrust of this program was to investigate the spectrum of N * and [Delta] * (non-strange) baryon resonances using photo-and electro-production reactions. To this end, final states containing strange particles (K mesons and low-mass hyperons) played a significant role. The reason for this is partly due to favorable kinemat-ics. When the total invariant energy W (= √ s) of a baryonic system exceeds 1.6 GeV it becomes possible to create the lightest strangeness-containing final state, K + [Lambda]. This is a two-body final state that is straightforward to reconstruct in the CLAS detector system [1], and theoretically it is easier to deal with two-body reaction amplitudes than with three-and higher-body reaction amplitudes. In the mass range W > 1.6 GeV the decay modes of excited nucleons tend to not to favor two-body [pi]-nucleon final states but rather multi-pion states. As input to partial-wave decompositions and resonance-extraction models, therefore, the strangeness-containing final states of high-mass nucleon excitations have had importance. Excited baryons decay through all possible channels simultaneously, constrained by unitarity of course, and channel-coupling is crucial to determining the spectrum of excita-tions. Within this mix of amplitudes, however, the KY decay modes have proven useful. The end result has been, as summarized in the recent edition of the Review of Particle Properties [2], clearer definition of the spectrum of baryonic excitations, with definite contributions from the strangeness sector channels. To this end, strangeness photoproduction cross sections measurements at CLAS for the K + [Lambda], K + [Sigma] 0 and K 0 [Sigma] + channels on a proton target were published [3-6]. Cross sections are not enough, in general, to define the reaction mechanism, including the underlying N * excitation spectrum. Photoproduction of pseudo-scalar mesons is described by four complex amplitudes, leading to fifteen spin observables in addition to the cross section. Full knowledge of these spin observables would exhaust the information that can be gleaned experimentally about any given reaction channel. Here the hyperonic channels offer another advantage when compared with the non-strange reaction channels: the polarization of most hyperons can be measured directly through their parity-violating weak decay asymmetries. Unlike 163.

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Languages : en
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An extensive program of strange particle production off the proton is currently underway with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Laboratory. This talk will emphasize strangeness photo- and electroproduction in the baryon resonance region between W =1.6 and 2.5 GeV, where indications of s-channel structure are suggestive of high-mass baryon resonances coupling to kaons and hyperons in the final state. Precision measurements of cross sections and polarization observables are being carried out with both electron and real photon beams, both of which are available with high polarization at energies up to 6 GeV.

Author: Kazushige Maeda
Publisher: World Scientific
ISBN: 981427786X
Category : Science
Languages : en
Pages : 469

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Importance of strange quarks in hadrons, nuclei and dense matter / A.W. Thomas -- Overview of strangeness nuclear physics / A. Gal -- Experimental overview and challenge in strangeness nuclear physics / K. Imai -- Recent QCD results on the strange hadron systems / M. Oka -- Strangeness physics with CLAS / V.D. Burkert -- Progress and issues in the electromagnetic production of kaon on the nucleon / T. Mart -- Neutral kaon photoproduction at LNS, Tohoku University / M. Kaneta et al. for the NKS/NKS2 collaboration -- Photoproduction of the [symbol] resonance from the neutron / K.H. Hicks and D. Keller for the LEPS collaboration -- Photo- and electroproduction of kaons / P. Bydz̮ouský -- Strangeness pproduction at ELSA / V. Kleber for the CBELSA/TAB collaboration -- Low Q[symbol] kaon electroproduction / P. Markowitz and A. Acha for the JLab E94-107 and Hall A collaborations -- Results on strangeness production from HADES / A. Schmah for the HADES collaboration -- [symbol] photo-production on the deuteron at LNS, Tohoku University / T. Ishikawa -- Current status of the GO parity violation experiment carried out at Jefferson Laboratory / L. Bimbot for the GO collaboration -- Production and searches for cascade baryons with CLAS / E.S. Smith for the CLAS collaboration -- Nijmegen Baryon-Baryon interactions S = -1,-2 systems / Th. A. Rijken, M.M. Nagels and Y. Yamamoto -- Hyperon-nucleus systems in G-matrix approach / Y. Yamamoto -- [symbol]C(O[symbol]) and [symbol]O potentials derived from the SU[symbol] quark-model Baryon-Baryon interaction / Y. Fujiwara, M. Kohno and Y. Suzuki

Author: M. Anselmino
Publisher: IOS Press
ISBN: 1607503484
Category : Science
Languages : en
Pages : 496

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Strangeness and Spin in Fundamental Physics is dedicated to the discussion of the role played by two subtle and somehow puzzling quantum numbers, the strangeness and the spin, in fundamental physics. They both relate to basic properties of the fundamental quantum field theories describing strong and electro-weak interactions and to their phenomenological applications. In some instances, like the partonic spin structure of the proton, they are deeply correlated. The many puzzling results recently obtained by measuring several spin asymmetries have stimulated gigantic progresses in the study of the spin structure of protons and neutrons. Intense theoretical activity has discovered new features of non-perturbative QCD, like strong correlations between the spin and the intrinsic motions of quarks inside the nucleons. The purpose of this publication is that of providing a complete, updated and critical account of the most recent and relevant discoveries in the above fields, both from the experimental and theoretical sides.

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Languages : en
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An extensive program of strange particle productian off the proton is currently underway with the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at Jefferson Laboratory. Precision measurements of ground-state and low-lying excited-state hyperons are being carried out with both electron and real photon beams, both of which are available with high polarization at energies up to 6 GeV. This talk will focus an selected aspects of our strangeness physics program regarding electroproduction measurements of single and double-polarization observables.

Author: Silvano Simula
Publisher: Springer Science & Business Media
ISBN: 3709168007
Category : Science
Languages : en
Pages : 387

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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.

Author: Il-t Cheon
Publisher: World Scientific
ISBN: 9814492752
Category : Science
Languages : en
Pages : 462

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The unique role of strangeness in nuclear physics has recently attracted much attention, from both the theoretical and experimental viewpoints. This is due not only to the broad spectrum of possible hadron many-body systems with strangeness, but also to the fact that strangeness gives us an opportunity to study fundamental baryon-baryon interactions in a new perspective. Our knowledge of this subject has widened as the scope of hypernuclear experiments has expanded from strangeness exchange and the associated production reactions to hypernuclear weak decays, β decays, cascade hypernuclei, double-Λ events, electroproduction of strangeness, etc. This trend will be accelerated by the full operation of new laboratories such as TJLab, COSY, DAΦNE, JHF, MAMI, and others. Various aspects of those important and exciting topics are discussed in this book in order to get a perspective of this fast developing area of nuclear physics.

Author: Kazushige Maeda
Publisher: World Scientific
ISBN: 9814483273
Category : Science
Languages : en
Pages : 475

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Book Description
This book contains important papers on the strangeness production processes and strangeness nuclear physics resulting from electromagnetic interaction. Both experimentalists and theorists in the field present information on recent activities and discuss the prospects of related fields.