CERN Shuts Down the Large Hadron Collider to Prepare Its High-Luminosity Upgrade

The LHC stopped colliding protons on June 29 and entered Long Shutdown 3, clearing the way for the High-Luminosity LHC, which aims for up to 10 times the collision rate when it starts in 2030.

CERN Shuts Down the Large Hadron Collider to Prepare Its High-Luminosity Upgrade The LHC stopped colliding protons on June 29 and entered Long Shutdown 3, clearing the way for the High-Luminosity LHC, which aims for up to 10 times the collision rate when it starts in 2030. Aaron Rafferty June 30, 2026 Key Takeaways CERN powered down the Large Hadron Collider on June 29 and entered Long Shutdown 3 to begin a major upgrade. The successor machine, the High-Luminosity LHC, is designed for up to 10 times the collision rate and is set to start in 2030. Researchers expect data on roughly 380 million Higgs bosons, a haul that could test the standard model and probe dark matter. Physicists have powered down the Large Hadron Collider , the machine that found the Higgs boson, and begun a years-long rebuild that will turn it into a far more powerful successor. The collider at CERN, the European physics lab near Geneva, stopped smashing protons on June 29 and entered what the lab calls Long Shutdown 3 . In its place, engineers will build the High-Luminosity LHC, scheduled to switch on in 2030. Since 2010 the LHC has accelerated protons around a 27-kilometer underground ring that straddles France and Switzerland, and its signature achievement came in 2012, when the ATLAS and CMS experiments used it to confirm the Higgs boson, the particle tied to the origin of mass. What the upgrade changes The new machine is built for volume. The High-Luminosity LHC is designed to deliver up to 10 times the luminosity of the current collider, a measure of how tightly packed the protons are in each beam, which translates into far more collisions to study. Getting there is not a quick tune-up. Crews will remove and replace about 1.2 kilometers of accelerator components, and the giant detectors that re