Unitarity Corrections to Pion-Pion Partial Wave Amplitudes from Dispersion Relation Formalism Original Research Article

In previous works we have compared the pion-pion scattering amplitude obtained from Chiral Perturbation Theory (ChPT) at one- and two-loop approximations with those obtained from dispersion relation formalism. The two approaches yield the same analytical structure to the amplitude at both approximation levels, while the unitarization procedure that uses dispersion relation integrals provides a more economic method than ChPT. This work give the tools for extending the use of the formalism in order to compute further unitarity corrections to partial waves.