| In this paper,under the theoretical framework of non-relativistic quantum chromodynamics(NRQCD),charmonium production rate was calculated by charmonium production process at super Tau-Charm factory.The energy region of the super Tau-charm factory was between 2 and 7 GeV,but(?)=7GeV is around the Charm production threshold since each Charm quartein has a mass of about 3 GeV.The three processes of e+e-?J/?+J/? and e+e-?J/?+?c as well as e+e-?J/?+?cJ are discussed and relativistic corrections are added to the calculations of each process.The e+e-?J/?+J/? cross section of the lead stage is in the range of 6-8 fb and reaches its peak at the center of mass energy of 7.0 GeV with a cross section of 8.53 fb The total cross section is about 0.4-0.8 fb and the K factor is in the range of 0.06-0.12 after adding the relativistic correction.The e+e-??c+?c add relativistic modified scattering cross sections at 0.002-0.01 fb.The K factor is in the range of-0.69 to 0.16.When the QCD modified K factor is only added in the range of 0.16-0.31.The e+e-?J/?+?c scattering cross section enhances the scattering cross section after considering the contribution of QED's relativistic modification.And the total cross section is 312.7-467 fb.The peak scattering cross section is 467 fb at 7 GeV The e+e-?J/?+?cJ relativistic correction for QED is low for the leading stage scattering cross section.After the e+e-?J/?+?c0 adding QCD and QED,the relativistic modified scattering cross section is about 40 fb and the K factor is in the range of 0.16-0.31.After e+e-?J/?+?c1 adding the modified scattering cross section is about 0.72 fb and the K factor is in the range of-0.004-0.11.After e+e-?J/?+?c2 adding the modified scattering cross section is about 0.3 fb and the K factor is in the range of 0.003-0.28.The scattering cross section of ?c1 and ?c2 is very small and difficult to observe in experiment. |
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