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Article
Deeply virtual and exclusive electroproduction of ω-mesons
The European Physical Journal A - Hadrons and Nuclei
  • L. Morand
  • Angela Biselli, Fairfield University
  • CLAS Collaboration, CLAS Collaboration
Document Type
Article
Publication Date
1-1-2005
Abstract

The exclusive ω electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross-sections were measured up to large values of the four-momentum transfer (- t < 2.7 GeV2) to the proton. The contributions of the interference terms σ{TT} and σ{TL} to the cross-sections, as well as an analysis of the ω spin density matrix, indicate that helicity is not conserved in this process. The t-channel π0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction γ* p→ωp, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross-sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.

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Copyright 2005 EDP Science with Springer

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Published Citation
L. Morand et al. [CLAS Collaboration], "Deeply virtual and exclusive electroproduction of ω-mesons," The European Physical Journal A - Hadrons and Nuclei 24.3 (2005) pp. 445-458.
DOI
10.1140/epja/i2005-10032-4
None
Peer Reviewed
Citation Information
L. Morand, Angela Biselli and CLAS Collaboration. "Deeply virtual and exclusive electroproduction of ω-mesons" The European Physical Journal A - Hadrons and Nuclei Vol. 24 Iss. 3 (2005)
Available at: http://works.bepress.com/angela_biselli/105/