Dual pomeron amplitude with external spin particles

Abstract On the basis of the operator‐formulation of the conventional dual resonance model we derive an expression for the one‐loop Pomeron exchange amplitude with four external excited particles lying on the parent Regge trajectory. Evaluation of the high energy behaviour leads to the definition of spin‐spin‐Pomeron form factors. There is a leading Pomeron contribution only if the sum of external spins is even. The dual Pomeron does not exhibit any helicity conservation properties except for s ‐channel forward scattering. The extension to multiloop amplitudes is briefly discussed.