By including the interference effect between the QCD and the QED diagrams, we carry out a complete analysis on the exclusive productions of e + e − → J/ψ + χ cJ (J = 0, 1, 2) at the B factories with √ s = 10.6 GeV at the next-to-leading-order (NLO) level in α s , within the nonrelativistic QCD framework. It is found that the O(α 3 α s)-order terms that represent the tree-level interference are comparable with the usual NLO QCD corrections, especially for the χ c1 and χ c2 cases. To explore the effect of the higherorder terms, namely O(α 3 α 2 s), we perform the QCD corrections to these O(α 3 α s)-order terms for the first time, which are found to be able to significantly influence the O(α 3 α s)order results. In particular, in the case of χ c1 and χ c2 , the newly calculated O(α 3 α 2 s)-order terms can to a large extent counteract the O(α 3 α s) contributions, evidently indicating the indispensability of the corrections. In addition, we find that, as the collision energy rises, the percentage of the interference effect in the total cross section will increase rapidly, especially for the χ c1 case.
Stone–Wales (SW) defects are possibly formed in graphene and other two-dimensional materials, and have multiple influence on their physical and chemical properties. In this study, the transition state of SW defects in graphene is determined with the fully discrete Peierls theory. Furthermore, the atomic formation process is investigated by means of ab-initio simulations. The atomic structure change and energetics of the SW transformation are revealed. It is found that the transition state is at the SW bond rotation of 34.5° and the activation energy barrier is about 12 eV. This work provides a new method to investigate SW transformations in graphene-like materials and to explore unknown SW-type defects in other 2D materials.
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