We study the question of whether calculations of deuteron photodisintegration respect gauge invariance, and show that the impulse approximation is in severe disagreement with gauge invariance. The method in which Siegert's theorem is implemented is consistent with gauge invariance to within ten percent. We introduce a modification of the impulse approximation in which the current is conserved exactly. For deuteron photodisintegration this method yields essentially the same results as that of Partovi. Our method can easily be applied to electron- or neutrinonucleus scattering.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}(\gamma , p)n$; impulse approximation versus gauge invariance.

• Received 24 April 1980

DOI:https://doi.org/10.1103/PhysRevC.22.968