Circular Electron Positron Collider

CEPC is projected to have a maximum center-of-mass energy of 240 GeV. It will be located underground, and have two detectors. The electron-positron collisions will allow clearer observations than the proton-proton collisions of the Large Hadron Collider (LHC). After 2040, the collider could be upgraded into the Super Proton–Proton Collider with collision energies seven times greater than the LHC. ==Physics program==

The CEPC enables a wide physics program. As an electron-positron collider, it is suited to precision measurements, but also has strong discovery potential for new physics. Some possible physics goals include: • Higgs measurements: Running slightly above the production threshold for ZH, the CEPC is a Higgs factory. Over the course of a ten-year run, it is planned to collect 5 ab−1 with two detectors, which corresponds to approximately one million produced Higgs Bosons. One target is to be able to measure the ZH production cross-section \sigma(ZH) to 0.5% accuracy. Other goals include the measurement of the Higgs Boson self coupling, and its coupling to other particles. • When running at the Z peak, a precision measurement of the Z Boson mass and other properties, e.g. the Zbb̅ coupling, can be made. • Physics beyond the Standard Model: Despite the lower center-of-mass energy compared to the LHC, the CEPC will be able to make discoveries or exclusions in certain scenarios where the LHC cannot. A prominent situation is when there is supersymmetry, but the masses of the superpartners are very close to each other (near-degenerate). In this case, when one SUSY particle decays into another plus a Standard Model particle, the SM particle will likely escape detection in a Hadron collider. In an e+e− collider, since the initial state is completely known, it is possible to detect such events by their missing energy (the energy carried away by SUSY particles and neutrinos). ==See also==