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Gamma* n delta form-factors from a relativistic dynamical model of pion electroproduction

Journal Article ·
OSTI ID:827026
We obtain the electromagnetic form factors of the {gamma}N{Delta} transition by analyzing recent pion-electroproduction data using a fully relativistic dynamical model. Special care is taken to satisfy Ward-Takahashi identities for the Born term in the presence of form factors thereby allowing the use of realistic electromagnetic form factors of the nucleon and pion. We parameterize the Q{sup 2} dependence of the bare {gamma}N{Delta} form factors by a three-parameter form which is consistent with the asymptotic behavior inferred from QCD. The parameters of the bare {gamma}N{Delta} form factors are the only free parameters of the model and are fitted to the differential cross-section and multipole-analysis data up to Q{sup 2} = 4 (GeV/c){sup 2} in the {Delta}(1232)-resonance region. This analysis emphasizes the significance of the pion-cloud effects in the extraction of the resonance parameters.
Research Organization:
Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
Sponsoring Organization:
USDOE Office of Energy Research (ER) (US)
DOE Contract Number:
AC05-84ER40150
OSTI ID:
827026
Report Number(s):
JLAB-THY-04-27; DOE/ER/40150-2821; nucl-th/0407069
Country of Publication:
United States
Language:
English