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Relativistic correction to e{sup +}e{sup -{yields}}J/{psi}+gg at B factories and constraint on color-octet matrix elements

Journal Article · · Physical Review. D, Particles Fields
; ;  [1]
  1. Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)
We calculate the relativistic correction to J/{psi} production in the color-singlet process e{sup +}e{sup -{yields}}J/{psi}+gg at B factories. We employ the nonrelativistic QCD factorization approach, where the short-distance coefficients are calculated perturbatively and the long-distance matrix elements are extracted from the decays of J/{psi} into e{sup +}e{sup -} and light hadrons. We find that the O(v{sup 2}) relativistic correction can enhance the cross section by a factor of 20-30%, comparable to the enhancement due to the O({alpha}{sub s}) radiative correction obtained earlier. Combining the relativistic correction with the QCD radiative correction, we find that the color-singlet contribution to e{sup +}e{sup -{yields}}J/{psi}+gg can saturate the latest observed cross section {sigma}(e{sup +}e{sup -{yields}}J/{psi}+X{sub non-cc})=0.43{+-}0.09{+-}0.09 pb by Belle, thus leaving little room to the color-octet contributions. This gives a very stringent constraint on the color-octet contribution, and may imply that the values of color-octet matrix elements are much smaller than expected earlier by using the naive velocity scaling rules or extracted from fitting experimental data with the leading-order calculations.
OSTI ID:
21409867
Journal Information:
Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 5 Vol. 81; ISSN PRVDAQ; ISSN 0556-2821
Country of Publication:
United States
Language:
English