Direct measurements of the cross sections for e+e−→hadrons|non-DD¯ in the range from 3.65 to 3.87 GeV and the branching fraction for ψ(3770)→non-DD¯

Abstract By tagging the largest energy of the assumed kaon in the final states of e + e − → hadrons , we measured the cross sections for e + e − → hadrons | non- D D ¯ in the range from 3.65 to 3.87 GeV. Analyzing these cross sections yields the branching fraction for the decay ψ ( 3770 ) → non- D D ¯ to be BF [ ψ ( 3770 ) → non- D D ¯ ] = ( 15.1 ± 5.6 ± 1.8 ) % , and the observed non- D D ¯ and D D ¯ cross sections to be σ had-non- D D ¯ obs = ( 1.08 ± 0.40 ± 0.15 )  nb and σ D D ¯ obs = ( 6.07 ± 0.40 ± 0.35 )  nb , respectively, at the center-of-mass energy E cm = 3.7724  GeV .