2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48226I discuss the status of ongoing work to determine numerically the elastic $ππ$ scattering amplitude at order $p^6$ in the framework of chiral perturbation theory.9 pages, Latex. Talk given at the International Workshop "Hadronic Atoms and Positronium in the Standard Model", Dubna, Russia, May 26-31, 1998. To appear in the ProceedingsHigh Energy Physics - Phenomenologytext