What Happened to European Organization for Nuclear Research (CERN) / Large Hadron Collider (LHC)?

The European Organization for Nuclear Research (CERN) and its flagship instrument, the Large Hadron Collider (LHC), have profoundly shaped our understanding of fundamental physics since its inception. Built between 1998 and 2008, the LHC was designed to probe the most basic constituents of matter and the forces governing them. Its primary objective was to discover the Higgs boson, a particle central to the Standard Model of particle physics, which explains how elementary particles acquire mass.

The LHC achieved its most celebrated breakthrough on July 4, 2012, with the announcement of the discovery of a new particle consistent with the Higgs boson by the ATLAS and CMS experiments. This landmark discovery confirmed a theoretical prediction made nearly half a century earlier and earned Peter Higgs and François Englert the Nobel Prize in Physics in 2013. Beyond the Higgs, the LHC has continued to operate in various 'runs,' pushing the boundaries of energy and luminosity, leading to the discovery of numerous new hadrons and providing crucial data to test the Standard Model and search for physics beyond it, including insights into dark matter and matter-antimatter asymmetry.

As of July 1, 2026, the LHC has entered a critical new phase: Long Shutdown 3 (LS3). This extensive maintenance and upgrade period, which officially began on June 29, 2026, will last approximately four years, with the accelerator complex and experimental facilities undergoing significant transformations. The flagship project during LS3 is the High-Luminosity Large Hadron Collider (HL-LHC), a major upgrade designed to dramatically increase the LHC's luminosity—the rate of particle collisions—by a factor of up to ten beyond its original design. This will allow researchers to collect vastly larger datasets, enabling precision studies of the Higgs boson and enhancing the potential to uncover rare phenomena and new physics beyond the Standard Model.

The HL-LHC upgrade involves replacing 1.2 km of magnets and components within the 27-kilometer ring, installing new superconducting 'crab' cavities, and extensively revamping the ATLAS and CMS detectors to cope with up to 200 proton-proton collisions per bunch crossing, compared to around 60 during the previous run. The civil engineering work for HL-LHC was completed in 2022, and the installation of components is now underway. The HL-LHC is scheduled to begin operation in 2030 and is expected to run until the 2040s, maintaining Europe's leadership in high-energy physics.

Looking further into the future, CERN is also actively pursuing plans for a successor to the LHC, the Future Circular Collider (FCC). In May 2026, the CERN Council endorsed the electron-positron version of the FCC (FCC-ee) as its preferred next flagship project. This proposed 91-kilometer underground ring, roughly three times the size of the LHC, would serve as a 'Higgs factory' to study the Higgs boson with unprecedented precision. Public consultations for the FCC project began in Switzerland and France in May and June 2026, respectively, as part of preparations for a final decision on the project, expected around 2028. The estimated cost for the FCC is around CHF 15 billion (approximately $19 billion), with CERN seeking diverse funding sources. If approved, the FCC-ee could be operational by the mid-2040s, with a potential future upgrade to a proton-proton collider (FCC-hh) reaching collision energies of up to 100 teraelectronvolts.