CERN Future Circular Collider study

CERN Future Circular Collider study
Name	Future Circular Collider study
Caption	Conceptual layout for the Future Circular Collider
Location	Geneva
Organization	CERN
Status	Study
Proposed	2019

CERN Future Circular Collider study The Future Circular Collider study is a conceptual research programme by CERN that explored large-scale accelerator options beyond the Large Hadron Collider; it assessed designs, technologies, physics reach, and implementation pathways. The study linked expertise from laboratories such as Fermilab, DESY, KEK, SLAC National Accelerator Laboratory, and universities including University of Oxford, Massachusetts Institute of Technology, University of Tokyo, Stanford University, and University of Cambridge to inform proposals for a new collider around Geneva and the Jura Mountains. The programme interfaced with policy bodies like the European Commission, funding agencies such as the European Research Council and national agencies including CNRS, INFN, and DOE for evaluation and coordination.

Background and motivation

The study grew from lessons of the Large Hadron Collider programme, the discovery at ATLAS and CMS of the Higgs boson, and strategic foresight exercises by advisory groups including the European Strategy for Particle Physics and the Particle Physics Project Prioritization Panel. Motivations cited include precision studies following Higgs boson measurements, exploration of energy frontiers beyond the Tevatron and complementarity with lepton colliders like proposals at CERN SPS predecessors, and maintaining leadership exemplified by institutions such as Institute for Advanced Study and collaborations like LHCb. The study also responded to global planning documents from panels including the International Committee for Future Accelerators and initiatives associated with IHEP Beijing and the National Science Foundation.

Design concepts and accelerator options

Design concepts examined a large tunnel (approximately 90–100 km) hosting multiple accelerator rings, with options including a high-energy hadron collider inspired by the Large Hadron Collider and an electron–positron collider serving as a Higgs factory akin to proposals like ILC and CLIC. Specific proposals considered a 100 TeV-class hadron collider, a 240–365 GeV electron–positron collider, and hybrid staging scenarios similar in intent to plans by KEK and concepts evaluated at CERN SPS and LEP. Technical architectures referenced superconducting magnet technology advanced by BNL and conductor developments involving companies such as Siemens and collaborations with materials groups at Max Planck Society and ETH Zurich. Accelerator complex integration engaged cryogenic suppliers with histories at Fermilab and magnet testing facilities at CERN Prévessin.

Physics goals and projected sensitivities

Goals included precision measurements of the Higgs boson couplings, searches for beyond-Standard-Model phenomena such as supersymmetric states investigated by ATLAS and CMS, dark matter candidates linked to experiments at LUX-ZEPLIN and XENONnT, and exploration of phenomena suggested by theoretical work from groups at Princeton University and University of California, Berkeley. Projections compared sensitivity to that of proposed machines like the International Linear Collider and the Compact Linear Collider, and cosmological constraints from collaborations such as Planck Collaboration and LSST Corporation. Studies estimated reach for rare processes studied at Belle II and flavour physics complementarity with LHCb, while neutrino program synergies referenced DUNE and Hyper-Kamiokande.

Technical challenges and research and development

R&D priorities covered high-field superconducting magnet development drawing on work at Brookhaven National Laboratory and NHMFL, radio-frequency systems influenced by DESY and SLAC National Accelerator Laboratory, cryogenics scaled from LHC practice, and beam dynamics research pursued at facilities like CERN Injector Complex and PSI. Materials science inputs referenced programmes at CERN Materials Laboratory and Oak Ridge National Laboratory for radiation-hard components, and detector advances built on technologies from ATLAS, CMS, ALICE, and LHCb. Infrastructure challenges considered civil engineering precedents from projects such as Channel Tunnel and tunnelling expertise from firms that worked on Gotthard Base Tunnel. Accelerator physics modelling relied on software historically developed at CERN and validated with experiments at SPS.

Cost, timeline, and governance

The study produced parametric cost estimates informed by capital projects at CERN and major programmes funded by agencies such as DOE Office of Science and CEA. Financial scenarios involved contributions from member states including France, Switzerland, Germany, Italy, United Kingdom, United States, China, and partners like Japan and Russia, with governance models compared to multinational projects such as ITER and collaborations like Square Kilometre Array. Timelines discussed staging consistent with technology maturation and coordination with strategies from the European Strategy Group; proposed schedules referenced milestones similar to those for LHC upgrades and the planning cycles of organizations like the European Research Area.

Environmental and societal considerations

Environmental assessments addressed land use around Geneva, groundwater and karst geology considerations in the Jura Mountains, and lessons from environmental impact reviews of infrastructure projects like Channel Tunnel and Gotthard Base Tunnel. Societal engagement strategies referenced outreach models used by CERN education programmes and public science projects associated with institutions such as Royal Society and National Academy of Sciences; workforce development and training drew on collaborations with universities including University of Oxford, University of Cambridge, and École Polytechnique Fédérale de Lausanne. Security, legal, and regulatory interactions were benchmarked against international frameworks involving bodies such as United Nations agencies and regional authorities in Canton of Geneva.

Category:Particle physics Category:Accelerators