China aims to start construction of world's biggest particle collider in 2027

China aims to start construction of its Circular Electron-Positron Collider (CEPC) in 2027, aligning with the country's 15th five-year plan, according to a recently unveiled design report on the project.

The project, estimated to cost approximately 36.4 billion yuan ($5.2 billion), is considerably cheaper to build and run than Europe's $17 billion Future Circular Collider (FCC). Construction on the European facility will begin in the 2030s if it receives government approval, according to the Nature magazine.

CEPC is a circular Higgs factory proposed by the Chinese particle physics community in 2012. The project, to be hosted in China in a circular underground tunnel of approximately 100 kilometers in circumference, is a double-ring collider with electron and positron beams circulated in opposite directions in separate beam pipes, and the detectors are installed at two interaction points.

It represents a crucial component of the global strategic plan for high energy physics. Once completed, it will foster collaboration among scientists worldwide and drive advancements in the understanding of the fundamental nature of matter, energy, and the universe, read a technical design report (TDR) on the project released on June 3.

The report, numbering more than 1,000 pages, is reportedly the first such report for a Higgs factory based on a circular collider.

The Higgs boson occupies a unique and fundamental position among all fundamental particles. It endows all other particles with their mass, and the mass of the Higgs has a direct bearing on all the other particles that make up our reality. Thus, the particle is believed by global physicists to be the best window to probe deeper into the fundamental nature of the universe.

According to the TDR, the CEPC team hopes to present the CEPC proposal (including accelerator, detector and engineering) for selection by the Chinese government around 2025. The construction of the CEPC is set to commence around 2027 and is projected to span 8 years, reaching completion by 2035. Post-commissioning, the tentative operational plan entails a 10-year duration dedicated to Higgs physics exploration, followed by successive 2-year and 1-year operations in Z mode and W mode, respectively.

The team has commenced site selection process in February 2015, according to the TDR. Preliminary geological studies for potential CEPC site locations have been conducted in various regions, including Qinhuangdao and Xiongan in North China's Hebei Province, Huangling County in North China's Shanxi Province, Huzhou in East China's Zhejiang Province, Changchun in Northeast China's Jilin province, and Changsha in Central China's Hunan Province. All of these sites meet the construction requirements for CEPC, read the report.

Being able to independently design such a large scientific facility demonstrates Chinese scientists' capabilities, Wang Yifang, director of the Institute of High Energy Physics (IHEP) of Chinese Academy of Sciences (CAS), told the Global Times in March.

In the next step, the scientists will proceed with the engineering design and integrate the completed components, according to Wang. "We have completed the construction of a single prototype, and the next step is to figure out how to mass-produce individual products. In addition, we will continue to conduct in-depth research on some key technical details to ensure that our facility achieves optimal performance and cost-effectiveness."