Nonlinear duality calculation of the width of the ππ diffraction peak

We insert Regge-exchange amplitudes into the unitarity relation at intermediate energies. The resulting ππ absorptive part is then required to be dual to one with Pomeranchukon (P), ρ, and f⁰ exchange. By assuming ρ and f⁰ residue functions consistent with the dual-absorptive model, we can then calculate the P residue near t=0.