Extended Siegert Theorem in the Relativistic Investigation of the Deuteron Photodisintegration Reaction

The contribution of the two-body exchange current is investigated for the reaction of the deuteron photodisintegration in the framework of the Bethe-Salpeter formalism and with using extended Siegert theorem. This theorem allow to express the reaction amplitude in terms of extended electric and magnetic dipole moments of the system. The resultant analytical expression is faultless with respect to both translation and gauge invariance. It permits to perform calculations of the deuteron photodisintegration cross section and polarization observables taking into account two-body exchange current implicitly.