Vertex operators for production of baryon resonances in nucleon-gamma collisions with preserving gauge invariance and analyticity

Abstract

Vertex operators for photo- and electro-production of baryon states with arbitrary spin-parity, $\gamma +N\to B(J^P)$, are constructed. The operators obey gauge invariance and analyticity constraints. Analyticity is realized as a requirement of the generalized Siegert theorem for vertex form factors.

Comments: 10 pages