Abstract
The so called final state interacions or rescattering effects give rise to large uncertainties in the cross sections of hadronic collisions. They are due to the fact that the hadrons produced in a collision may suffer non-negligible interactions between themselves before reaching the detector. A recently proposed effective theory [1] may be instrumental to systematically address this problem. We propose to initially explore this issue in the scattering of scalar particles, and eventually in the relevant case of the Chiral Lagrangian [2].