# Electromagnetic-transition form factors free of kinematic singularities

Research paper by W. R. Theis, P. H. Hertel

Indexed on: 21 Jan '16Published on: 21 Jan '16Published in: Il Nuovo Cimento A (1971-1996)

#### Abstract

Matrix elements of the electromagnetic currents between one-particle states of spins ands′ are decomposed into invariant functions free of kinematic singularities which are the usual multipole amplitudes in the nonrelativistic limit. Parity conservation is taken into account. Kinematic constraints occur only at the two physical threshold values and are given explicitly.