2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177431Using 58 million J/psi and 14 million psi' decays obtained by the BESII experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous measurements.9 pages, 8 figures, RevTex4High Energy Physics - Experimenttext