2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177468Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.11 pages, 6 figuresHigh Energy Physics - Experimenttext