2019 Impact factor 2.176
Hadrons and Nuclei
Eur. Phys. J. A 5, 417-428

Gauge constraints and electromagnetic properties of off-shell particles

S.I. Nagorny1,2 - A.E.L. Dieperink3

1 Nationaal Instituut voor Kernfysica en Hoge-Energiefysica, P.O. Box 41882, 1009, DB Amsterdam, The Netherlands
2 Free University of Amsterdam, Deptartment of Physics and Astronomy, de Boelelaan 1081, 1081, HV Amsterdam, The Netherlands
3 Kernfysisch Versneller Instituut, 9747, AA Groningen, The Netherlands

Received: 23 March 1999 Communicated by V.V. Anisovich

The consequences of the gauge constraints for off-shellness in the electromagnetic (EM) vertices have been considered, using Compton scattering as an example. We have found that even if the gauge constraint for the 3-point EM Green function allows for off-shell effects in the charge (Dirac) form factor, they vanish in the total Compton scattering amplitude due to the gauge constraint for the 4-point EM Green function only. In addition, the representations of the Compton amplitude in terms of either reducible or irreducible vertices are equivalent for conserved currents.

13.40.Gp Electromagnetic form factors - 13.60.Fz Elastic and Compton Scattering - 14.70.Bh Photons

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