Nucleon-nucleon scattering phase shifts by the Nambu-Salpeter-Bethe equation

A numerical solution of the NSB equation (BS equation) is investigated in the two-channel states. The interaction is assumed to be the ladder exchange of pi-mesons, and pair creation effects in the intermediate states are neglected. In the 3S1 + 3D1 wave the channel-coupling effect is very strongly attractive and a bound state is found. It is seen that the channel-coupling effect is so large that the classification of states by the orbital angular momentum is doubtful even in an approximate sense. The effect of the iteration of the rungs is rather small in the 3P2 + 3F2 wave, but the channel-coupling effect is fairly large even in this wave.