The High Luminosity Large Hadron Collider

The High Luminosity Large Hadron Collider (HL-LHC) is a major upgrade of the Large Hadron Collider (LHC) that is completed by 2026. This new design boosts the machine's luminosity by a factor of between five and seven, allowing 10 times more data to be accumulated, providing a better chance to see rare processes and improving statistically marginal measurements.

Luminosity is a way of measuring the performance of an accelerator: it is proportional to the number of collisions that occur in a given amount of time. The HL-LHC can perform detailed studies of the new particles observed at the LHC, such as the Higgs boson. It enables the observation of rare processes that were inaccessible at the previous sensitivity levels. More than 15 million Higgs bosons can be produced each year, for example, compared to the 1.2 million produced in 2011-2012.

The development of the HL-LHC depends on several technological innovations that are exceptionally challenging to researchers – such as cutting-edge Tesla superconducting magnets, very compact and ultra-precise superconducting cavities for beam rotation, and 300-metre-long high-power superconducting links with zero energy dissipation. Together, these upgrades help to advance and further refine the knowledge already gained from the Higgs boson and provide fresh insights into so-called "New Physics", a more fundamental and general theory than that of the Standard Model.