Deeply virtual and exclusive electroproduction of omega mesons
The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q{sup 2}) 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 GeV{sup 2}) to the proton. The contributions of the interference terms sigma{sub TT} and sigma{sub TL} to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi{sup 0} exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction {gamma}* p {yields} omega p, even for Q{sup 2} as large as 5 GeV{sub 2}. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behavior of the cross sections is nearly Q{sup 2}-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 839446
- Report Number(s):
- JLAB-PHY-05-326; DOE/ER/40150-3346; hep-ex/0504057; TRN: US0501698
- Resource Relation:
- Other Information: No journal information given for this preprint; PBD: 1 Apr 2005
- Country of Publication:
- United States
- Language:
- English
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