High-Luminosity LHC

High-Luminosity LHC. The High-Luminosity LHC is a major upgrade project for the Large Hadron Collider (LHC) at the CERN laboratory. Its primary objective is to significantly increase the integrated luminosity, or data output, of the collider by a factor of ten beyond the original design. This enhancement will enable physicists to study rare processes with greater precision and collect vastly larger datasets, crucial for exploring physics beyond the Standard Model.

Overview

The project represents the culmination of the LHC's long-term development plan, following the initial operations that led to the discovery of the Higgs boson. Approved by the CERN Council in 2016, it is an international endeavor involving dozens of institutions worldwide. The upgrade focuses on the ATLAS and CMS detectors, the two general-purpose experiments that made the landmark Higgs discovery. By pushing the accelerator and detectors to their ultimate performance, the initiative aims to secure the future of the LHC physics program well into the 2040s, ensuring CERN remains at the forefront of particle physics research.

Technical upgrades

The core technical challenge involves replacing and enhancing critical components around the ATLAS and CMS interaction points. Key innovations include the installation of new, more powerful superconducting quadrupole magnets, known as the Inner Triplet, which will squeeze particle beams to a smaller size. This is complemented by advanced crab cavities, a technology developed in part through KEK and the LHC Accelerator Research Program (LARP), to tilt bunches of protons for more effective collisions. The entire machine will also utilize upgraded beam dumps and collimators to handle the more intense beams safely. Furthermore, the experiments' detectors are undergoing extensive upgrades, such as new silicon trackers and calorimeters, to withstand the extreme radiation environment and higher data rates.

Physics goals

The primary physics goal is to make precision measurements of the properties of the Higgs boson, such as its couplings to other particles like the top quark and bottom quark, to test the predictions of the Standard Model with unprecedented accuracy. Scientists aim to investigate rare Higgs decay channels and probe for potential CP violation in the Higgs sector. The vast dataset will also enable more sensitive searches for new particles predicted by theories like supersymmetry and for phenomena such as dark matter candidates produced in collisions. Additionally, studies of the quark-gluon plasma in heavy-ion runs with instruments like the ALICE detector will benefit from the increased collision rates.

Project timeline and status

The project was formally launched after the approval of the Technical Design Report in 2015. Major civil engineering work, including the excavation of new underground halls near the ATLAS and CMS sites, began in 2018. The installation of new machine components is scheduled during the third long shutdown (LS3) of the LHC, currently planned from 2026 to 2028. Commissioning of the upgraded accelerator chain is expected to follow, with the start of physics operations under high-luminosity conditions targeted for 2029. The project will then operate through the 2030s and into the early 2040s, collecting data concurrently with other future projects like the proposed Future Circular Collider.

Collaborating institutions

The project is a global collaboration coordinated by CERN. Major contributing institutions include the U.S. Department of Energy and the National Science Foundation through the LHC Accelerator Research Program, which developed key magnet technology. Laboratories such as Fermilab, Brookhaven National Laboratory, and Lawrence Berkeley National Laboratory play leading roles. In Europe, partners include INFN in Italy, CNRS in France, and the Science and Technology Facilities Council in the United Kingdom. Significant contributions also come from institutes in Asia, including KEK in Japan and the Institute of High Energy Physics in China, as well as from collaborators in nations like Canada, Russia, and India.

Category:Particle accelerators Category:CERN Category:Physics experiments