CERN experiments

CERN experiments constitute the core scientific activity of the European Organization for Nuclear Research, probing the fundamental constituents of matter and the forces governing the universe. These investigations are conducted using some of the world's most powerful particle accelerators and sophisticated particle detectors, built and operated by global collaborations of thousands of physicists and engineers. The research programme has produced landmark discoveries, from the confirmation of the Standard Model to the exploration of new physics frontiers, solidifying CERN's role as a premier hub for high-energy physics.

Overview of CERN's experimental programme

The experimental programme is structured around a suite of accelerator complexes, each designed to collide particles at specific energy frontiers to test theoretical predictions. The flagship is the Large Hadron Collider, the world's most powerful hadron collider, which operates at energies up to 13.6 TeV. Other critical facilities include the Proton Synchrotron, the Super Proton Synchrotron, and the Antiproton Decelerator, each serving distinct research goals from fundamental collisions to antimatter studies. Experiments range from large, general-purpose detectors seeking new particles to smaller, precision instruments measuring specific properties, all governed by a rigorous peer review process conducted by the CERN Research Board.

Major particle detectors and accelerators

The LHC hosts four major experiments: ATLAS and CMS are general-purpose detectors that discovered the Higgs boson; ALICE studies the quark–gluon plasma state of matter; and LHCb investigates asymmetries between matter and antimatter. Preceding accelerators in the injector chain, like the Proton Synchrotron Booster, feed particles into the LHC. Elsewhere on site, facilities like ISOLDE produce radioactive isotopes for nuclear physics, while the NA62 at the SPS North Area studies rare kaon decays. The Antiproton Decelerator supplies low-energy antiprotons to experiments like BASE and ALPHA.

Key discoveries and scientific results

The most celebrated discovery is the observation of a Higgs boson by the ATLAS and CMS teams in 2012, a cornerstone of the Standard Model predicted by Peter Higgs and François Englert. Earlier Nobel Prize-winning work includes the 1983 discovery of the W and Z bosons by the UA1 and UA2 collaborations, led by Carlo Rubbia and Simon van der Meer. Experiments at the Large Electron–Positron Collider precisely tested the electroweak interaction. More recent results include detailed measurements of CP violation by LHCb, studies of quark–gluon plasma at ALICE, and stringent limits on supersymmetry and dark matter candidates from LHC data.

Future experiments and upgrade projects

The primary near-term project is the High-Luminosity LHC upgrade, scheduled for the 2029–2030 period, which will increase integrated luminosity by a factor of ten. This will enable experiments like ATLAS and CMS to collect vastly more data for precision Higgs studies and searches for rare processes. Future proposed facilities include the Future Circular Collider, a potential successor to the LHC, and the Compact Linear Collider study. The Physics Beyond Colliders initiative explores complementary experiments using CERN's accelerator complex, while projects like the SHiP experiment aim to search for very weakly interacting particles.

International collaboration and data analysis

CERN's experiments are characterized by unprecedented global partnerships, such as the ATLAS collaboration which involves over 180 institutions from 42 countries. Data from collisions is processed through the Worldwide LHC Computing Grid, a distributed computing infrastructure spanning over 170 centers in 42 countries, including major hubs like Brookhaven National Laboratory and INFN. The CERN open data policy makes certain datasets available to the public and researchers worldwide. These massive collaborations are coordinated under frameworks like the CERN Council and involve long-term partnerships with institutions such as Fermilab, KEK, and the Joint Institute for Nuclear Research.

Category:Particle physics Category:Scientific experiments Category:Research and development