Future Circular Collider

Future Circular Collider
Name	Future Circular Collider
Location	CERN
Type	Particle accelerator
Site	Geneva

Future Circular Collider. The Future Circular Collider is a proposed post-Large Hadron Collider particle accelerator complex envisioned to be constructed at the CERN laboratory near Geneva. Its primary scientific mission is to push the energy and intensity frontiers of particle physics, serving as a Higgs boson factory and a discovery machine for phenomena beyond the Standard Model. The ambitious project is designed as a circular collider housed in a new 90–100 km circumference tunnel, significantly larger than the existing LHC ring.

Overview and Purpose

The overarching purpose is to provide a transformative tool for fundamental physics research in the latter half of the 21st century. It aims to build upon the legacy of the LHC and its landmark discovery of the Higgs boson by studying its properties with unprecedented precision. The project is conceived as a multi-decade program under the European Strategy for Particle Physics, intended to maintain Europe's leadership in high-energy physics. Its design allows for sequential stages, beginning with an electron-positron collider to meticulously probe known physics, followed by a proton-proton collider to explore uncharted energy territories.

Design and Technical Specifications

The baseline design centers on a new underground tunnel of approximately 91 kilometers in circumference, which would be bored beneath the Jura Mountains and the Lake Geneva region in France and Switzerland. The first proposed stage, the FCC-ee, would collide electrons and positrons at center-of-mass energies ranging from 90 GeV to 365 GeV, operating as an ultra-high-luminosity Z boson, W boson, Higgs boson, and top quark factory. A subsequent stage, the FCC-hh, would repurpose the same tunnel to collide protons at energies up to 100 TeV, far surpassing the LHC's 14 TeV, requiring advanced superconducting magnet technology. The infrastructure would also accommodate a possible electron-proton collision mode, FCC-eh.

Physics Goals and Scientific Potential

The FCC-ee stage promises exquisitely precise measurements of the Higgs boson, electroweak symmetry breaking, and the properties of the Z and W bosons, offering stringent tests for theoretical inconsistencies. It will perform detailed studies of the top quark and search for rare decays and potential light, weakly-interacting particles. The FCC-hh stage is a powerful discovery machine designed to directly produce new particles at multi-TeV mass scales, probe the nature of dark matter, investigate the asymmetry between matter and antimatter, and explore the conditions of the early universe moments after the Big Bang.

Project Timeline and Stages

The project is currently in the feasibility study and technical design phase, with a formal proposal expected around 2025-2027. Following approval and funding decisions, a lengthy construction period of approximately 15-20 years is anticipated. The envisioned timeline would see the FCC-ee begin operations in the late 2040s, following the conclusion of the High-Luminosity LHC program. After 15-20 years of data collection, the tunnel would be refurbished to install the FCC-hh, with proton-proton collisions potentially starting in the 2070s. This staged approach mirrors the evolution from the Large Electron–Positron Collider to the LHC.

Comparison with Other Colliders

Compared to the 27-km LHC, the FCC's larger circumference allows for higher proton energies with similar magnet technology and reduces synchrotron radiation losses for leptons. The proposed Compact Linear Collider, another CERN concept, is a linear electron-positron collider offering complementary advantages at higher energies but without the circular machine's luminosity and energy-upgrade path. Internationally, it would operate in a landscape that includes China's proposed Circular Electron Positron Collider and the Super Proton–Proton Collider, as well as Japan's International Linear Collider project, fostering global scientific competition and collaboration.

Cost, Funding, and International Collaboration

Preliminary cost estimates for the entire multi-decade program range in the tens of billions of euros, with the initial FCC-ee stage estimated at approximately €15 billion. Funding would require an unprecedented global partnership, extending far beyond CERN's current member states. The project's realization hinges on the formation of a broad international consortium, potentially involving major contributions from nations like the United States, Japan, China, and others. The scale necessitates a long-term political and financial commitment similar to that which enabled the ITER fusion project and the LHC itself.

Category:Particle accelerators Category:Proposed scientific infrastructure Category:CERN