Circular Electron Positron Collider

<h2 id="description">Description</h2>
CEPC is projected to have a maximum center-of-mass energy of 240 GeV.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> It will be located 100 metres (330 ft) underground, and have two detectors.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> The electron-positron collisions will allow clearer observations than the proton-proton collisions of the <a href="/facts/Large_Hadron_Collider/XWJCFSqT">Large Hadron Collider</a> (LHC).<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>
After 2040, the collider could be upgraded into the Super Proton–Proton Collider<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a> with collision energies seven times greater than the LHC.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a>

<h2 id="physics-program">Physics program</h2>
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:

<ul><li>Higgs measurements: Running slightly above the production threshold for ZH, the CEPC is a <a href="/facts/Higgs_factory/JdXytahI">Higgs factory</a>. 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.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a> One target is to be able to measure the ZH production cross-section 
 
 
 
 σ
 (
 Z
 H
 )
 
 
 {\displaystyle \sigma (ZH)}
 
 to 0.5% accuracy. Other goals include the measurement of the Higgs Boson self coupling, and its coupling to other particles.</li>
<li>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.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a></li>
<li><a href="/facts/Physics_beyond_the_Standard_Model/UX68py44">Physics beyond the Standard Model</a>:<a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> 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 <a href="/facts/Supersymmetry/hkWGrMet">supersymmetry</a>, 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).</li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Large_Electron%25E2%2580%2593Positron_Collider/8hxB4TKe">Large Electron–Positron Collider</a> – LEP was the highest energy lepton collider ever built</li>
<li><a href="/facts/Compact_Linear_Collider/6o8RWUFd">Compact Linear Collider</a> – another post-LHC linear particle accelerator planned at <a href="/facts/CERN/y1gwRchm">CERN</a></li>
<li><a href="/facts/International_Linear_Collider/4vjdo4QB">International Linear Collider</a> – another post-LHC linear particle accelerator planned in Japan</li>
<li><a href="/facts/Future_Circular_Collider/aqD44oJl">Future Circular Collider</a> – a proposed 100 TeV circular collider at CERN</li></ul>

<h2 id="external-links">External links</h2>
<ul><li>Record for <a href="https://inspirehep.net/experiments/1620741">CEPC</a> on <a href="/facts/INSPIRE-HEP/CDEYl9E1">INSPIRE-HEP</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">"The CEPC Project". Institute of High Energy Physics. Retrieved 26 December 2021. <a href="http://cepc.ihep.ac.cn/intro.html" target="_blank">http://cepc.ihep.ac.cn/intro.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Gao, Jie; Li, Yuhui; Yu, Chenghui (27 March 2024). "China's designs for a future circular collider". CERN Courier. Retrieved 28 March 2024. <a href="https://cerncourier.com/a/chinas-designs-for-a-future-circular-collider/" target="_blank">https://cerncourier.com/a/chinas-designs-for-a-future-circular-collider/</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Gao, Jie; Li, Yuhui; Yu, Chenghui (27 March 2024). "China's designs for a future circular collider". CERN Courier. Retrieved 28 March 2024. <a href="https://cerncourier.com/a/chinas-designs-for-a-future-circular-collider/" target="_blank">https://cerncourier.com/a/chinas-designs-for-a-future-circular-collider/</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"The CEPC Project". Institute of High Energy Physics. Retrieved 26 December 2021. <a href="http://cepc.ihep.ac.cn/intro.html" target="_blank">http://cepc.ihep.ac.cn/intro.html</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">"The CEPC Project". Institute of High Energy Physics. Retrieved 26 December 2021. <a href="http://cepc.ihep.ac.cn/intro.html" target="_blank">http://cepc.ihep.ac.cn/intro.html</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Gibney, Elizabeth (23 November 2018). "Inside the plans for Chinese mega-collider that will dwarf the LHC". Nature. doi:10.1038/d41586-018-07492-w. S2CID 115440460. Retrieved 26 December 2021. <a href="https://www.nature.com/articles/d41586-018-07492-w" target="_blank">https://www.nature.com/articles/d41586-018-07492-w</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">LOU, Xinchou. "Overview of the CEPC project" (PDF). Workshop on Physics at the CEPC, August 10–12, 2015 <a href="http://indico.ihep.ac.cn/event/4937/session/0/contribution/1/material/slides/1.pdf" target="_blank">http://indico.ihep.ac.cn/event/4937/session/0/contribution/1/material/slides/1.pdf</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">Gu, Jiayin. "Probing Zbb̅ couplings at the CEPC" (PDF). Workshop on Physics at the CEPC, August 10–12, 2015 <a href="http://indico.ihep.ac.cn/event/4937/session/2/contribution/15/material/slides/0.pdf" target="_blank">http://indico.ihep.ac.cn/event/4937/session/2/contribution/15/material/slides/0.pdf</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">Craig, Nathaniel. "Naturalness and Higgs Measurements" (PDF). Workshop on Physics at the CEPC, August 10–12, 2015 <a href="http://indico.ihep.ac.cn/event/4937/session/1/contribution/7/material/slides/0.pdf" target="_blank">http://indico.ihep.ac.cn/event/4937/session/1/contribution/7/material/slides/0.pdf</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
</ol>

Circular Electron Positron Collider open-in-new

Circular Electron Positron Collider