CERN Begins Long Shutdown 3 for High-Luminosity LHC Upgrade

CERN has officially begun Long Shutdown 3 (LS3), a major maintenance and upgrade phase for the Large Hadron Collider (LHC). This ambitious program, which started on June 29, 2026, involves extensive work to prepare the accelerator for the High-Luminosity LHC (HiLumi LHC). During LS3, 1.2 kilometers of magnets and components will be replaced, and the ATLAS and CMS experiments will undergo significant upgrades to handle the increased collision rates expected when the HiLumi LHC begins operations around 2030.