Measurements of Charm and Charmonium Decays at BES

Abstract

By analyzing data collected with the BES-II detector at the BEPC collider, a lot of charm and charmonium decays were studied. We directly measured the branching fractions for ψ ( 3770 ) → non − D D ¯ to be (15.1 ± 5.6 ± 1.8)%, and searched for 39 decay modes of ψ(3770) → light hadrons. We firstly observed anomalous line-shape of cross sections near 3.770 GeV. The branching fractions for the neutral and charged D inclusive semileptonic decays are directly measured. We observed Y(2175) in the decay J / ψ → η Φ f 0 ( 980 ) . A lot of channels for ψ ( 2 s ) → γ + hadrons with the invariant mass of hadrons below 2.9 GeV were studied.