The S₁₁-P₁₁ phase shifts of pion-nucleon scattering

The S₁₁ and P₁₁ partial amplitude is calculated using the N/D method. The present calculation differs from the previous ones in the handling of the divergent behavior of the forces due to first-order diagrams, by parameterizing the short-range forces, and in the way of including inelasticity. We obtain the nucleon as a bound state with correct mass and residue and the correct S₁₁ and P₁₁ scattering lengths. The calculated S-wave and P-wave phase shifts and absorption coefficients are in substantial agreement with those from the CERN Theoretical and Almehed-Lovelace phase shift analyses.