Recently, Professor Wu Lei from the School of Physics and his team members Peter Athron, Andrew Fowlie, Lu Zhiting, and Wu Yongcheng, as well as Associate Professor Zhu Bin from Yantai University, made important research progress in the field of precise measurement fitting of electroweak interactions and new physics. The relevant results were published in Nature Communications under the title "Hadronic Uncertainties versus New Physics for the W boson Mass and Muon g-2 Anomalies" (Nature Communications 14 (2023) 659), with Nanjing Normal University as the first unit.

Since the establishment of the Standard Model of Particle Physics in the 1960s, it has undergone a large number of experimental verifications. In recent years, with the advancement of experimental techniques, high-precision testing of the Standard Model at the quantum level has become an important means of searching for new physics beyond the Standard Model. In April 2021, the Fermi National Accelerator Laboratory in the United States announced the latest world average value of the muon anomalous magnetic moment, and in April 2022, the CDF-II experiment group published the most accurate measurement results of the W boson mass in a cover article in Science. Both of these have significant deviations from the theoretical predictions of the Standard Model, becoming two new "clouds" in particle physics and attracting widespread attention from physicists around the world.

Fig. 1 The correlation betwee Mw and Muon g-2 in the electroweak fit.

Professor Wu Lei's team noticed that the contribution of hadronic vacuum polarization is not only a key part of the theoretical calculation of the Standard Model's Muon g-2, but it can also contribute to the running of the fine structure constant through Dahad, making it a key factor in precise electroweak fitting. By using precise electroweak observables, including the most accurate W boson mass, the research team provided a highly competitive theoretical result for the contribution of hadronic vacuum polarization, independent of e+e- and lattice calculations, and predicted the Standard Model value for Muon g-2. The results showed that the Standard Model cannot perfectly reconcile the experimental data of precise electroweak measurements and Muon g-2, providing new impetus for new physics research. Based on this, the research team constructed a new scalar leptoquark model to solve this problem, and this leptoquark new particle can be detected in the Run-3 Large Hadron Collider (LHC) experiment, providing very important theoretical guidance for the search for new physics beyond the Standard Model.

This research was supported by the National Natural Science Foundation of China, the Institute of Theoretical Physics at Nanjing Normal University, the Peng Huanwu Science and Education Cooperation Center, and the Institute of Advanced Physics and Cross-Disciplinary Science at Nanjing Normal University.

Link to the paper: https://www.nature.com/articles/s41467-023-36366-7