Recently, Professor Feng Feng from the Department of Physics and the Experimental Teaching Center at our university, serving as the corresponding author, has published a research paper titled “Optimized O (αs2) Correction to Exclusive Double J/ψ Production at B Factories” in the esteemed physics journal Physical Review Letters (PRL). This marks another research achievement by Professor Feng Feng, following two previous articles where he served as the first author in the same journal. The research received support from the National Natural Science Foundation of China, the Sino-German Cooperation Fund, and involved collaboration with Jia Yu and his research group from the Institute of High Energy Physics, Chinese Academy of Sciences, as well as Sang Wenlong from the Strong Particle Physics Team at School of Physical Science and Technology, Southwest University.

The process of double J/ψ production at the Electron-Positron Collider serves as an ideal platform for investigating both perturbative and non-perturbative effects in Quantum Chromodynamics (QCD). Over the past two decades, it has been a focal point in QCD research. The process е+е-→j/ψ+j/ψ, despite possessing a highly clean experimental signal has not been detected to date. In 2008, researchers Gong Bin and Wang Jianxiong from the Institute of High Energy Physics calculated the next-to-leading-order QCD corrections for this process and discovered a significant negative correction at the single-loop level. This finding has been considered a partial explanation for the lack of experimental detection of this process.

Through careful analysis, the authors identified that the high-order Feynman diagrams for double J/ψ production through independent two-photon fragmentation are the main cause of the non-convergence of perturbation theory. Therefore, they proposed an improvement plan to decompose the perturbative fixed-order diagrams into fragmentation and non-fragmentation parts in a gauge-invariant way. For the fragmentation part, they used the experimentally precisely measured J/ψ lepton decay width as input, which is equivalent to re-summing all high-order corrections corresponding to the fragmentation part, effectively avoiding the non-convergence of the perturbative expansion. The contribution of the non-fragmentation part can be obtained through the traditional NRQCD factorization scheme. The study showed that the perturbative convergence of the optimized NRQCD predictions becomes very good. In the end, the authors provided the most accurate predictions for the J/ψ distribution and total cross-section to date. This theoretical research suggests that there is a promising possibility of observing this process in the future Super B Factories.