Total cross sections for the H(π+,π+π+)n reaction have been measured at pion kinetic energies of 180, 184, 190 and 200 MeV. The threshold value for the matrix element a(π+π+) and the s-wave, isospin-2, ππ scattering length a20 were determined. The results were found to be in agreement with chiral perturbation theory and inconsistent with the model of dominance by quark loop anomalies.
