On Nucleon Electromagnetic Form Factors

A Poincaree-covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is solved to obtain masses and Faddeev amplitudes for the nucleon and D. The amplitudes are a component of a nucleon-photon vertex that automatically fulfills the Ward-Takahas...

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Veröffentlicht in:Few-body systems 2005-07, Vol.37 (1-2), p.1-31
Hauptverfasser: Alkofer, R., Höll, A., Kloker, M., Krassnigg, A., Roberts, C. D.
Format: Artikel
Sprache:eng
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Zusammenfassung:A Poincaree-covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is solved to obtain masses and Faddeev amplitudes for the nucleon and D. The amplitudes are a component of a nucleon-photon vertex that automatically fulfills the Ward-Takahashi identity for on-shell nucleons. These elements are sufficient for the calculation of a quark core contribution to the nucleons electromagnetic form factors. An accurate description of the static properties is not possible with the core alone but the error is uniformly reduced by the incorporation of meson-loop contributions. Such contributions to form factors are noticeable for Q2.2 GeV2 but vanish with increasing momentum transfer. Hence, larger Q2experiments probe the quark core. The calculated behaviour of GpEQ2=GpMQ2 on Q2 22; 6 GeVOn Nucleon Electromagnetic Form Factors2 agrees with that inferred from polarization transfer data. Moreover,Q2 p F2Q2=F1Q2 constant on this domain. These outcomes result from correlations in the protons amplitude. [PUBLICATION ABSTRACT]
ISSN:0177-7963
1432-5411
DOI:10.1007/s00601-005-0110-6