The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community in 2012 to explore the aforementioned physics program. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km 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 (IPs). The CEPC will operate in three different modes: H (e+e- -->ZH), Z (e+e- -->Z) and W (e+e- -->W+W-). The center-of-mass energies are 240 GeV, 91 GeV and 160 GeV, and the luminosities are 3×1034, 32×1034 and 10 ×1034 cm-2s-1, respectively. The primary physics goal is to use the CEPC as a Higgs factory. Therefore, a tentative “7-2-1” operation plan is to run first as a Higgs factory for 7 years and create one million Higgs particles or more, followed by 2 years of operation as a Super Z factory to create one trillion Z bosons and then 1 year as a W factory to create about 100 million W bosons. The vast amount of bottom quarks, charm quarks and τ-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and τ-charm factory. The CEPC offers an unmatched opportunity for precision measurements and searches for BSM physics.
Preliminary machine parameters for the electron
positron collider have been calculated and listed in the table below:
The figure shows our current concept of a timeline for the CEPC project. It consists of the following stages:
- The first stage is to complete a Preliminary Conceptual Design Report (PreCDR) in 2015 and a Conceptual Design Report (CDR) in 2018. With the publication of this report, these goals have been achieved.
- The next stage is a 5-year period from 2018 to 2022 for R&D and for completion of a Technical Design Report (TDR)
- Construction will start in 2022 in the government’s 14th Five-Year Plan and continue in the 15th Five-Year Plan. Construction will be completed by 2030.
- Experiments can begin as early as 2030 when the 16th Five-Year Plan starts.
- The experiments will continue for about 10 years until 2040.
- After 2040, the superconducting magnets for the SPPC project are expected to
be ready for installation, and the SPPC era will begin.
CEPC is conducting country wide site visits and study. Local government agencies are very receptive and supportive to CEPC. CDR study is based on site 1 (Qing Huang Dao). The site selection is still in processing, and CEPC team keep looking for more site candidates in China.