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QCD corrections to e+e- -->J/psi+gg at B factories
Yan-Qing Ma1, Yu-Jie Zhang, Kuang-Ta Chao
1Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
Physical Review Letters
|June 13, 2009
Summary
New calculations in nonrelativistic QCD address discrepancies in heavy quarkonium production. Next-to-leading-order corrections significantly improve fits to the J/psi + cc-bar ratio, aiding understanding of color-octet contributions.
Area of Science:
- High Energy Physics
- Quantum Chromodynamics
- Particle Physics
Background:
- Heavy quarkonium production at B factories shows a measured ratio (R_cc-bar) significantly larger than theoretical predictions.
- Existing theoretical models struggle to explain the observed J/psi + cc-bar production cross sections.
Purpose of the Study:
- To resolve the discrepancy between theoretical predictions and experimental measurements of heavy quarkonium production.
- To investigate the impact of next-to-leading-order (NLO) QCD corrections on J/psi production ratios.
Main Methods:
- Calculated the NLO QCD correction to the e+e- -> J/psi + gg process within nonrelativistic QCD.
- Incorporated the NLO result for e+e- -> J/psi + cc-bar production.
- Considered leading logarithm resummation effects on J/psi momentum distributions and total cross sections.
Main Results:
- The NLO QCD correction to e+e- -> J/psi + gg enhances the cross section by approximately 20%.
- Including NLO corrections for both e+e- -> J/psi + gg and e+e- -> J/psi + cc-bar processes significantly improves the fit to the measured R_cc-bar ratio.
- Leading logarithm resummation effects were analyzed for J/psi momentum distributions.
Conclusions:
- NLO QCD corrections are crucial for accurately describing heavy quarkonium production, particularly the J/psi + cc-bar ratio.
- Comparison of theoretical cross sections for e+e- -> J/psi + gg with experimental data for J/psi + non-(cc-bar) can provide insights into color-octet contributions.
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