2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/37534Measurements of branching fractions for nine different final states, based on a data sample of approximately 4 million psi(2S) events collected with the BESI detector at the BEPC, are reported. Using the same event sample, radiative decays of the psi (2S) into pi pi, K K-bar and eta eta final states have been measured. Cross sections for e e -> e e, hadrons, pi pi J/psi, and mu mu have been measured in the vicinity of the psi(2S) resonance using the BESII detector. The psi(2S) total width; partial widths to hadrons, pi pi J/psi and muons; and corresponding branching fractions have been determined. Decays of J/psi -> gamma eta_c are used to determine the mass and width of the eta_c using a sample of 58 M J/psi events. $M_{η_c} = (2977.5 \pm 1.0 \pm 1.2)$ MeV and $Γ_{η_c} = (17.0 \pm 3.7 \pm 7.4)$ MeV. The first observation of chicJ (J=0,1,2) decays to lambda lambda-bar is reported using psi(2S) data collected with the BESII detector. Results are compared with model predictions.8 pages with 12 figures, invited talk at the International Symposium on Hadron Spectroscopy, Chiral Symmetry and Relativistic Description of Bound States, Nihon University, Ichigaya, Tokyo, February 24-26, 2003High Energy Physics - Experimenttext