Measurements of the cross sections for e + e − → hadrons at 3.650, 3.6648, 3.773 GeV and the branching fraction for ψ ( 3770 ) → non- D D ¯

Measurements of the cross sections for e + e − → hadrons at 3.650, 3.6648, 3.773 GeV and the branching fraction for ψ ( 3770 ) → non- D D ¯