[Paper Review] Snowmass2021 White Paper AF3-CEPC

CEPC Accelerator Study Group|arXiv (Cornell University)|Mar 15, 2022

Particle Accelerators and Free-Electron Lasers13 citations

TL;DR

This Snowmass2021 white paper presents the technical design and R&D progress of the Circular Electron Positron Collider (CEPC), a proposed 100 km circular collider in China designed to serve as a Higgs boson factory at 240 GeV center-of-mass energy, with potential upgrades to a Super Proton-Proton Collider (SppC). The paper details optimized accelerator design, luminosity performance, power consumption, cost estimates, and a staged construction timeline, advancing CEPC toward conceptual and technical readiness for future high-energy physics research.

ABSTRACT

The discovery of the Higgs boson at Large Hadron Collider (LHC) of CERN in July 2012 raised new opportunities for large-scale accelerators. The Higgs boson is the heart of the Standard Model (SM) and is at the center of many biggest mysteries.In September 2012, Chinese scientists proposed a 240 GeV Circular Electron Positron Collider (CEPC) as a Higgs Factory, having two large detectors for Higgs studies and other topical researches. The 100 km tunnel of CEPC could also host a Super proton proton Collider (SppC) to reach energies well beyond the LHC. CEPC Conceptual Design Report (CDR) has been released in Nov. 2018, and in this CEPC Accelerator White Paper to Snowmass21 AF3, CEPC Technical Design Report (TDR) status with optimized design and key technology R and D progresses have been reported. The energy range, luminosity, upgrade and staging potentials, power consumption, cost, readiness assessment, timelines, construction and operation plans, etc. are covered.

Motivation & Objective

• To present the current technical design report (TDR) status of the CEPC accelerator, building on the 2018 Conceptual Design Report (CDR).
• To report on key technology R&D progress essential for CEPC's feasibility and performance.
• To assess the readiness, cost, power consumption, and timeline for construction and operation of the CEPC-SppC project.
• To evaluate the upgrade and staging potential of the CEPC infrastructure for future high-energy physics experiments.
• To support the scientific case for CEPC as a next-generation Higgs factory and future collider facility in the global particle physics landscape.

Proposed method

• The CEPC accelerator design is based on a 100 km circumference tunnel optimized for electron-positron collisions at 240 GeV center-of-mass energy.
• The design includes two large detectors for high-precision Higgs boson measurements and studies of new physics beyond the Standard Model.
• The same tunnel is designed to host a future Super Proton-Proton Collider (SppC) with center-of-mass energy exceeding that of the LHC.
• Key technologies such as superconducting RF cavities, high-gradient accelerating structures, and advanced beam dynamics simulations are under active R&D.
• The paper evaluates beam dynamics, lattice design, and cryogenic systems to ensure high luminosity and long-term stability.
• A staged construction approach is proposed, starting with the CEPC phase followed by the SppC upgrade, with detailed cost and timeline projections.

Experimental results

Research questions

• RQ1 What is the current technical readiness level of the CEPC accelerator design, and how does it compare to the 2018 CDR?
• RQ2 What are the key technological challenges and progress in R&D for CEPC, particularly in superconducting RF and beam dynamics?
• RQ3 What is the projected luminosity, power consumption, and cost for the CEPC phase, and how do they compare to international benchmarks?
• RQ4 How feasible is the staged upgrade from CEPC to SppC, and what are the technical and logistical constraints?
• RQ5 What is the timeline for construction, commissioning, and operation of the CEPC-SppC project?

Key findings

• The CEPC accelerator design has been optimized in the Technical Design Report (TDR) phase, with detailed engineering and physics performance parameters now established.
• Key R&D progress has been achieved in superconducting RF cavities, high-gradient accelerating structures, and beam dynamics simulations, enhancing technical feasibility.
• The CEPC phase is projected to achieve high luminosity at 240 GeV center-of-mass energy, enabling precision Higgs boson measurements.
• The 100 km tunnel infrastructure is designed to support a future SppC upgrade with center-of-mass energy significantly exceeding the LHC.
• Power consumption and cost estimates have been refined, with a detailed construction and operation timeline proposed for both CEPC and SppC phases.
• The project is assessed as technically ready for the next phase of design and international collaboration, with strong support from the Chinese scientific community.