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Nanjing Normal University joined the Belle II International Collaboration

From October 18-25, 2019, the Belle II 34th Collaboration meeting was held in Japan, and Nanjing Normal University (NNU) became its ninth Chinese member. Professor Kai Yi (contact person) and Associate Professor Bin Zhong from the School of Physics and Technology are the first two members from NNU.

Professor Kai Yi, together with Associate Professor Bin Zhong led NNU to join the Belle II International Collaboration, and formed the NNU PPNP group, which is now more advanced in theoretical physics research than in experimental research. They reached out to the previous existing Chinese Belle II groups and got their strong support, especially in hardware development. For instance, the Belle II team at Fudan University extended their hands to NNU by helping them join the Belle II KLM (K-long and muon) detector project. All Chinese Belle II groups together helped NNU to join the Belle II collaboration in various aspects.


Professor Kai Yi (left) and  Associate Professor Bin Zhong (right)

A model of SuperKEKB, picture provided by Belle II

When asked about the status of the Nanjing Normal University particle physics program Professor Kai Yi replied, “The Particle Physics and Nuclear Physics (PPNP) group in the School of Physics and Technology at Nanjing Normal University (NNU) is an established group with 16 faculty members and 32 postdocs and postgraduate students. The group is composed of two teams – the theory team and the experiment team. The theory team has made significant contributions to B meson physics, hadron physics, as well as physics beyond the standard model. The recent achievements in hadron physics include, for example, a successful prediction of the exotic hadron--Pc (4312) state and the double-peak structure at the position of exotic hadron--Pc (4450) state which was confirmed by the LHCb experiment. The experiment team joined the Beijing Electron-Positron Collider experiment, and made corresponding contributions to the experiment since it became a formal member of the BES III collaboration in 2005.”

NNU will start its work at Belle II from an experimental work aspect, in another words, it will provide service work for the collaboration. As a starting point, NNU will participate in the maintaince of the KLM system through taking expert shifts, and then participating in the possible upgrade of this sub-system with responsibility for a specific project.

As for research projects, NNU is planning to conduct research in exotic hadron physics and search for new physics through rare processes by taking advantage of Prof Yi’s rich experience in these topics. He participated in the conformation of X (3872) particle at CDF. As a main contributor, he discovered exotic particles at CDF—initially called Y (4140) and Y (4274), and now called chi_c (4140) and chi_c (4274).    

Photo provided by Belle II

The Belle II is an experiment at the SuperKEKB accelerator in Japan aiming to solve this great mystery of particle physics. From 1998 to 2010, KEK, the Japanese High-Energy Accelerator Research Organisation, operated KEKB, a 3 km circumference asymmetric electron-positron collider thereby reaching the world record in instantaneous luminosity of 2.1x1034 cm–2s-1. The beam energies were chosen so that in the collisions large numbers of B-anti-B meson pairs were produced, and hence the facility is also known as a B factory.

An upgrade of both the accelerator and detector of the Belle experiment started in 2010, which was also the start of the Belle II experiment. The Belle II accelerator (SuperKEKB) was designed to achieve peak luminosity at a factor of forty times higher than the Belle accelerator, and all the Belle II sub-detectors have been upgraded to have a much better performance. The Belle II experiment, one of the intensity frontiers in the world, started to take data this spring.

The Belle II collaboration has about 1000 collaborators from more than 100 institutions in 26 different counties; each member contributes to the experiment in a collaborative manner through various efforts. For instance, by constructing part of the detectors, coordinating detector or data analysis work, reviewing collaboration papers, as well as performing data analysis.