Improved Pion Pion Scattering Amplitude from Dispersion Relation Formalism.

Pion-pion scattering amplitude is obtained from Chiral Perturbation Theory at one- and two-loop approximations. Dispersion relation formalism provides a more economic method, which was proved to reproduce the analytical structure of that amplitude at both approximation levels. This work extends the use of the formalism in order to compute further unitarity corrections to partial waves, including the D-wave amplitude. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]