A New Treatment Below the Three-Body Break up Threshold in the NN

The two-body threshold behavior at NN′ and πD are investigated by using the multi-channel Lippmann-Schwinger equations with an energy dependent two-body quasi potential, which are analytically continued from the three-body Faddeev equations at the three-body break up threshold. Our calculated NN′ and πD scattering lengths show better agreement with the experimental data for NN and πD systems than those from the original NNπ three-body Faddeev equations