Low-Energy Pion-Pion Scattering

Abstract
A general method for solving the problem of low-energy pion-pion scattering is presented. Within each partial wave, the nearby unphysical singularities are calculated by the usual Chew-Mandelstam approach, while the more distant ones are treated by a generalization of the Ball-Wong technique. These two techniques are then combined with the requirement of self-consistency. A rough calculation is given in which only a narrow P-wave resonance is retained, and the only free parameter is the pion mass. The resulting resonance has a mass of 585 MeV and a half-width of 125 MeV. A method is also given for calculating Regge poles at low energies.