Reduced fermi-motion effect by kinematical corrections in diffractive leptoproduction of heavy quarkonium Original Research Article

The diffractive leptoproductions of heavy vector mesons J/Ψ and Ψ′ off a nucleon are studied with perturbative QCD, focusing on effects of the Fermi motion due to relative transverse momentum kτ between c and View the MathML source inside the vector meson. Those effects are calculated under the constraint to ensure the S-wave View the MathML source states in the vector meson light-cone wave functions. We find that proper treatment of that constraint moderates the strong suppression of the diffractive production cross sections due to the previous improper one, demonstrating key roles of the Fermi-motion effects when confronting with experimenting data of the Ψ′ production as well as J/Ψ production from HERA.