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    After the LHC: the debate over the next big collider

    In May 2026 CERN named the electron-positron Future Circular Collider its preferred successor to the LHC, but its estimated 15 billion Swiss franc first stage exceeds CERN's budget and a go/no-go decision is due by 2028.[1][2][3][4] The debate is now about money and alternatives, including scaled-down designs, a muon collider and China's shelved CEPC.[5][6][7]

    Editor reviewedUpdated Particle physics and cosmologyPhysicsScience
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    Where things stand

    The large-hadron-collider stopped on 27 June 2026 for a rebuild into the High-Luminosity LHC. That machine is due to run from 2030, with operations extending to 2041.[8][9][10] On 22 May 2026 the CERN Council named the electron-positron future-circular-collider (FCC-ee) the preferred next flagship.[1] It asked CERN management to develop a financially feasible funding plan with member states, non-member states and the EU, and will decide by 2028.[4]

    The physics case

    The FCC would be a 90.7 km ring. Its first stage is a Higgs factory designed to study the Higgs boson’s interactions in detail and search for physics beyond the Standard Model. A later proton stage would reach around 100 TeV.[11][12][13] The High-Luminosity LHC will itself produce at least 15 million Higgs bosons a year.[14]

    Supporters see a Higgs factory as the logical next step because the Higgs boson is the least-tested part of the Standard Model. The weakness of the case is that, unlike the LHC’s search for the Higgs, no new particle is guaranteed. FCC-ee is a precision machine whose value lies in finding small deviations, if they exist.

    The money

    CERN estimates the electron-positron stage at 15 billion Swiss francs over about 12 years from the early 2030s.[2] Physics Today reported that the price exceeds what CERN can pay from its budget, requiring several billion francs more.[3] Slightly more than a third of the cost is tunnel excavation.[15] A descoped design with two interaction sites, 40% less RF power and no top-quark programme would save about 15%.[5] Member states may struggle to pay more as many raise defence spending because of the war in Ukraine.[16] The pressure is not new. In 2024 Germany’s research ministry said it could not afford the FCC and called the financing plan “extremely vague”.[17] In June 2026 Director-General Mark Thomson said he was “reasonably optimistic” about raising the roughly €16.5 billion needed.[18]

    Because the tunnel is a fixed cost, descoping saves relatively little. The realistic choice is between finding new money, from non-member states, the EU or elsewhere, and delaying. A slower build is a plausible compromise, but it would widen the gap after the High-Luminosity LHC ends.

    The alternatives

    Physics Today described the main alternatives, linear colliders and circular colliders reusing the LHC tunnel, as inferior.[19] Not everyone agrees. In a January 2026 Physics World opinion piece, Michael Riordan argued that CERN needs a more modest “Plan B”. He cited two linear-collider options at roughly €10 billion and an LEP3 collider in the existing tunnel at under €5 billion, though LEP3 would be limited to 240 GeV.[20] The US P5 panel supported hosting a muon collider at Fermilab and a significant US in-kind contribution to an offshore Higgs factory.[6] China’s 100 km CEPC was left out of its 2026-2030 five-year plan. Its lead scientist said China would resubmit in 2030 or seek to join the FCC if it is approved first.[7][21]

    With CEPC on hold, FCC-ee has no near-term rival Higgs factory. That strengthens CERN’s hand in seeking international partners. It also means that if FCC funding fails, the world may have no new energy-frontier collider before the 2040s.

    What may happen next

    The key milestones are CERN management’s annual progress reports to the Council and the decision due by 2028.[4] We think approval of some form of FCC-ee by 2028 is more likely than not, given the Council’s formal backing in the 2026 strategy. Approval may come with a longer construction schedule or reduced scope, and a decision slipping past 2028 is a real possibility. A US or Chinese commitment to join would be the strongest signal that funding is coming together.[6][21]

    Competing views

    Build FCC-ee as planned

    The CERN Council's 2026 strategy calls FCC-ee the broadest exploratory programme in fundamental physics, and a feasibility study has defined its 90.7 km tunnel and 15 billion franc cost. Physics Today described the alternatives as inferior.[1][11][2][19]

    Funding forces a smaller or slower project

    The cost exceeds CERN's budget by several billion francs, Germany said in 2024 it could not afford the project, member states face rising defence spending, and a descoped two-experiment version would save only about 15%.[3][17][16][5]

    Prepare a cheaper Plan B

    Physicist and historian Michael Riordan argues that geopolitics make a third of the cost from non-members unrealistic, and that CERN should ready a linear collider (about €10 billion) or an LEP3 machine in the LHC tunnel (under €5 billion).[20]

    Invest in other technologies, such as a muon collider

    The US P5 roadmap backs hosting a muon collider at Fermilab while contributing to an offshore Higgs factory.[6]

    Questions readers ask

    Has the FCC been approved?

    No. The CERN Council named FCC-ee its preferred next flagship in May 2026 and will decide on it by 2028, after a funding plan is developed.[1][4]

    Why is the FCC so expensive?

    Slightly more than a third of the total cost is for digging the 91 km tunnel, which leaves little room for savings.[15]

    What happened to China's competing collider?

    CEPC was not included in China's 2026-2030 five-year plan. Its lead scientist said it would be resubmitted in 2030 unless the FCC is approved first, in which case China would seek to join the FCC.[7][21]

    Sources

    Each numbered claim is a statement we checked against the sources listed with it. Status shows how well established it is.

    1. [1]

      On 22 May 2026 the CERN Council updated the European Strategy for Particle Physics, naming the electron-positron Future Circular Collider as the preferred next flagship project. confirmedas of 2026-05-22

    2. [2]

      CERN estimates the cost of building the FCC electron-positron stage, including the tunnel and infrastructure, at 15 billion Swiss francs, spread over about 12 years from the early 2030s. confirmedas of 2025-03-31

    3. [3]

      Physics Today reported in June 2026 that the FCC's 15.3 billion Swiss franc price exceeds what CERN can pay from its budget, requiring several billion francs in additional funding. reportedas of 2026-06-18

    4. [4]

      The CERN Council asked CERN management to develop a financially feasible funding plan for FCC-ee with member states, other countries and the EU, will receive annual progress reports from management, and will decide on the project by 2028. confirmedas of 2026-05-22

    5. [5]

      A scaled-down FCC with two interaction sites instead of four, 40% less radiofrequency power and no top-quark programme could save about 15% of the cost. reportedas of 2026-06-18

    6. [6]

      The December 2023 US P5 report recommended early implementation of DUNE, a significant US in-kind contribution to an offshore Higgs factory, and supported hosting a muon collider at Fermilab. confirmedas of 2023-12-08

    7. [7]

      China's proposed 100 km Circular Electron-Positron Collider (CEPC), whose technical design reports were completed in October 2025, was not included in China's 15th Five-Year Plan for 2026 to 2030. confirmedas of 2026-10-10

    8. [8]

      Proton beams circulated in the LHC for the last time before Long Shutdown 3 on 27 June 2026; the final proton-proton collisions took place on 16 May and the final lead-lead collisions on 14 June. confirmedas of 2026-07-23

    9. [9]

      During Long Shutdown 3, 1.2 km of LHC magnets and components are being replaced; the accelerator complex is due to restart gradually from 2028 and the High-Luminosity LHC to begin operating in 2030. confirmedas of 2026-06-29

    10. [10]

      The 2026 European Strategy update keeps completing the High-Luminosity LHC as the highest medium-term priority, with operations extending to 2041. confirmedas of 2026-05-22

    11. [11]

      The proposed Future Circular Collider would have a 90.7 km ring at an average depth of 200 metres under France and Switzerland. confirmedas of 2026-10-10

    12. [12]

      CERN describes the FCC as a Higgs factory designed to study the Higgs boson and its interactions in detail, and to search for dark matter candidates and other physics beyond the Standard Model. confirmedas of 2026-10-10

    13. [13]

      The FCC plan has two stages, an electron-positron collider (FCC-ee) working as a Higgs factory first, followed by a proton-proton collider (FCC-hh) at a collision energy of around 100 TeV. confirmedas of 2025-03-31

    14. [14]

      CERN expects the High-Luminosity LHC to produce at least 15 million Higgs bosons a year, compared with about three million from the LHC in 2017. confirmedas of 2026-10-10

    15. [15]

      Slightly more than a third of the FCC's total cost is for excavating the tunnel, leaving little room for cost cutting, according to Physics Today's reporting. reportedas of 2026-06-18

    16. [16]

      Physics Today reported that CERN member states may be too squeezed to pay more than their existing contributions, as many are raising defence spending because of the war in Ukraine. reportedas of 2026-06-18

    17. [17]

      In May 2024 Germany's research ministry, a major CERN funder, said it could not afford to fund the FCC and called its financing plan "extremely vague". reportedas of 2024-05-28

    18. [18]

      In June 2026 CERN Director-General Mark Thomson said he was "reasonably optimistic" about securing the roughly €16.5 billion needed to build the FCC, whose cost Research Professional News described as controversial. reportedas of 2026-06-10

    19. [19]

      Physics Today's report described the alternatives to the FCC, linear colliders and circular colliders reusing the LHC tunnel, as inferior. reportedas of 2026-06-18

    20. [20]

      In a January 2026 Physics World opinion piece, physicist and historian Michael Riordan argued that geopolitics make it unrealistic to expect non-member countries to fund a third of the FCC, put FCC-ee's cost at about $18 billion with operations around 2050, and urged CERN to prepare a cheaper "Plan B" such as linear colliders (roughly €10 billion) or an LEP3 collider in the LHC tunnel (under €5 billion, up to 240 GeV). confirmedas of 2026-01-29· interpretation

    21. [21]

      CEPC's lead scientist said the project would be resubmitted in 2030 unless the FCC is approved first, in which case China would seek to join the FCC. confirmedas of 2026-10-10

    Revision history (2)
    1. Page created.
    2. Added an independent FCC critic (Michael Riordan's Plan B argument) as a separate view, and further funding sources (Germany 2024, Thomson 2026).

    Created Oct 10, 2026. Last reviewed by an editor on Oct 10, 2026. Next scheduled review: Jan 10, 2027.

    Cite this page

    "After the LHC: the debate over the next big collider." ContentLora, updated Oct 10, 2026. https://contentlora.com/analysis/next-collider-debate

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