The mid-term report of the Future Circular Collider (FCC) feasibility study demonstrates significant progress across all project deliverables, including physics opportunities, the placement and implementation of the ring, civil engineering, technical infrastructure, accelerators, detectors and cost (pp25–38). While further work is to be done, no technical showstoppers have been found. From the perspective of the technical schedule alone, operations of the Higgs, electroweak and top factory FCC-ee could start in the early 2040s.
In China, a technical design report for the Circular Electron–Positron Collider demonstrates significant progress towards a facility that could operate in the second half of the 2030s, along with excellent prospects for approval and funding (p39). Meanwhile in the US, there is renewed interest in colliding muons, for which major technology challenges remain (p45).
All proposed future colliders have a rich physics case rooted in deeper investigation of the Higgs sector, and Europe needs to move fast to minimise the gap between the LHC and the next collider at CERN (p43). If the feasibility study shows that the FCC can be afforded, then it represents the best available option for the future of CERN and particle physics.