Feynman-like rules for the dual-resonance model on the basis of the Nakanishi decomposition

We present Feynman-like rules for the dual-resonance model, whose counting rule is the same as in the conventional field theory. Our approach is based on the Nakanishi decomposition of the n-point Veneziano formula. This decomposition is extended to general loop amplitudes. One advantage of this scheme is that the periodicity problem for the loop amplitudes is automatically removed, at least at the one-loop level.