Construction is scheduled to begin in 2026 and is expected to take approximately five years. The cost of the project, which will give China a leading position in s-quark and tau-lepton research, is 4.5 billion yuan.

What is known

The new collider is intended to be the successor to the Beijing Electron-Positron Collider (BEPC), which became operational in 1990. It consists of 240-meter underground tunnels where particles accelerate to speeds close to the speed of light collide and form various subatomic particles. The spectrometer records their trajectories, energies and electrical charges to reconstruct the course of the reaction.

This collider, which has an energy of up to 5 gigaelectron volts in the beam, has already made a number of important discoveries, especially in the field of s-quarks and tau-leptons. For example, in 1996, scientists used BEPC to precisely measure the mass of tau particles. It is planned to use it for another ten years, until the early 2030s, but its location and relatively small storage ring do not allow to reach a new level of accuracy of research. Therefore, a new collider is needed.

The Super Charm Tau Factory (STFC) project was proposed in 2011. In addition to scientists from the People’s Republic of China, approximately 500 experts from 74 universities in different countries also agreed to participate in the project. Its design is generally the same as the BEPC but is twice the size. Length of accelerator 400 metersand the length of the two rings for the accumulation of electrons and positrons 800 meters each. New accelerator technologies and an advanced spectrometer will make it possible to work with energy up to 7 gigaelectron volts and a brightness approximately 100 times higher.

Such properties would be sufficient to verify whether a tetraquark, for example, really has four quarks. So how does the force that binds them together work?