Precision measurements of the mass, the widths of ψ(3770) resonance and the cross section σ[e+e−→ψ(3770)] at Ecm=3.7724GeV

By analyzing the R values measured at 68 energy points in the energy region between 3.650 and 3.872 GeV reported in our previous paper, we have precisely measured the mass, the total width and the leptonic width of the ψ(3770) resonance to be Mψ(3770)=3772.4±0.4±0.3MeV, Γψ(3770)tot=28.5±1.2±0.2MeV and Γψ(3770)ee=277±11±13eV, respectively. We have measured the leptonic branching fraction of the ψ(3770) decays and the ψ(3770) production cross section at its peak to be B[ψ(3770)→e+e−]=(0.97±0.03±0.05)×10−5 and σprd[e+e−→ψ(3770)]=10.0±0.3±0.5 nb, respectively. The latter one results in the corresponding observed cross section of σobs[e+e−→ψ(3770)]=7.2±0.2±0.4 nb. We have also measured Ruds=2.121±0.023±0.084 for the continuum light hadron production in the region from 3.650 to 3.872 GeV.