LHC shuts down after smashing records in 2025's groundbreaking run

The Large Hadron Collider (LHC) has entered its annual winter shutdown after a record-breaking year. Located near Geneva on the Swiss-French border, the world’s most powerful particle accelerator will now prepare for a major upgrade. This pause follows a highly productive 2025, during which the machine achieved unprecedented collision rates and expanded its research scope. The LHC operates in a 27-kilometre circular tunnel, accelerating protons to nearly the speed of light. When these particles collide, scientists analyse the debris to uncover the universe’s fundamental properties. In 2025, the collider surpassed all previous records by generating over 500 inverse femtobarns (fb⁻¹) of data—more than any prior year.

All four of the LHC’s main detectors—ALICE, CMS, ATLAS, and LHCb—functioned at over 90% efficiency throughout the year. The collider also broke new ground by conducting specialised collision cycles, including protons with oxygen ions, oxygen with oxygen, and neon with neon. These experiments marked a first for the facility. The current operational phase, known as Run 3, will end in June 2026. After this, the LHC will undergo a multi-year transformation into the High-Luminosity LHC. This upgrade aims to boost luminosity tenfold compared to the original design. Once complete, the enhanced machine could produce up to 15 million Higgs bosons annually by the mid-2030s—a significant leap from the 3 million recorded in 2017.

The shutdown follows a successful 2025 campaign and sets the stage for a major upgrade. The High-Luminosity LHC will enable more precise measurements and increase the discovery potential for rare particles. Work is expected to resume after the winter break, with the next phase of operations concluding in mid-2026.