Dispersion approach to the calculation of three-particle bound states and contributions of three-particle unitarity
Grach I.L. , Narodetskn I.M., Shmatikov M. Zh.
The following are demonstrated: 1) the equivalence of the single-channel N/D method to the pole approximation in the Amado model, and 2) the need for taking into account three-particle, s -channel unitarity in the calculation (within the framework of the dispersion method) of the ground and excited states of a three-particle system.