V Burkert

Publications (2)0 Total impact

• Source

  Available from: arxiv.org

  Article: Theory Support for the Excited Baryon Program at the Jlab 12 GeV Upgrade

  I. Aznauryan, V. Braun, V Burkert, S. Capstick, R. Edwards, I. C. Cloet, M. Giannini, T. -S. H. Lee, H. -W. Lin, V Mokeev, C. D. Roberts, E. Santopinto, P Stoler, Q Zhao, B. S. Zou
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  ABSTRACT: This document outlines major directions in theoretical support for the measurement of nucleon resonance transition form factors at the JLab 12 GeV upgrade with the CLAS12 detector. Using single and double meson production, prominent resonances in the mass range up to 2 GeV will be studied in the range of photon virtuality $Q^2$ up to 12 GeV$^2$ where quark degrees of freedom are expected to dominate. High level theoretical analysis of these data will open up opportunities to understand how the interactions of dressed quarks create the ground and excited nucleon states and how these interactions emerge from QCD. The paper reviews the current status and the prospects of QCD based model approaches that relate phenomenological information on transition form factors to the non-perturbative strong interaction mechanisms, that are responsible for resonance formation. Comment: 52 pages, 19 figures, White Paper of the Electromagnetic N-N* Transition Form Factor Workshop at Jefferson Lab, October 13-15, 2008, Newport News, VA, USA
  07/2009;
• Chapter: Electroexcitation of the Roper resonance from CLAS data

  I. Aznauryan, V. Burkert
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  ABSTRACT: The helicity amplitudes of the electroexcitation of the Roper resonance on proton are extracted at 1.7 < Q 2 < 4.2 GeV 2 from recent high precision JLab-CLAS cross sections data and longitudinally polarized beam asymmetry for π + electroproduction on protons. The analysis is made using two approaches, dispersion relations and unitary isobar model, which give consistent results. It is found that the transverse helicity amplitude for the γ*p → P 11(1440) transition, which is large and negative at Q 2 = 0, becomes large and positive at Q 2 ≃ 2 GeV 2, and then drops slowly with Q 2. Longitudinal helicity amplitude, that was previously found from CLAS data as large and positive at Q 2 = 0.4, 0.65 GeV 2, drops with Q 2. These results rule out the presentation of P 11(1440) as a q 3 G hybrid state, and provide strong evidence in favor of this resonance as a first radial excitation of the 3q ground state.
  12/2007: pages 231-233;