The Large Hadron Collider Goes Quiet for Three Years
After a productive extension, Run 3 at the LHC concluded in early July 2026. The machine now enters Long Shutdown 3 for a major upgrade.
The biggest story in particle physics this year isn’t a discovery — it’s a shutdown. CERN confirmed that the final physics beams were dumped at the end of June, closing out an extended and unusually productive Run 3 and beginning Long Shutdown 3, a pause expected to last up to four years.
Shutdowns like this aren’t downtime in any meaningful sense; they’re when the actual rebuilding happens. Long Shutdown 3 is the window for the High-Luminosity LHC upgrade — new focusing magnets, upgraded detectors, and infrastructure changes designed to let the machine deliver several times more collision data per year once it restarts, with first High-Luminosity operations now targeted for 2030. None of that work is possible with beam circulating, so the field’s attention now shifts from the collision floor to the installation schedule.
It’s also a natural moment to take stock. Run 3 pushed the LHC’s collected dataset well past anything the experiments had before, and the analysis backlog from that data will keep theorists and experimentalists busy for years regardless of what the machine itself is doing. New particle observations, precision measurements of known ones, and searches for anomalies will keep coming out of Run 3 data long after the tunnel goes quiet.
There’s something fitting about a field this obsessed with continuity treating a shutdown as a headline. The next time protons circulate at these energies, the machine delivering them will be meaningfully different — and that’s the whole point.