The Large Hadron Collider is a particle accelerator at CERN using two counter-circulating beams in a roughly 27-kilometre underground ring. It collides protons and can also operate with heavy ions. Superconducting magnets steer and focus the beams, while radiofrequency electric fields add energy along their direction of motion.[ref]
Large Hadron Collider by CERN. Accelerator description: ring, beam types, magnets and accelerating structures
The functional division matters: an ideal static magnetic field bends a particle's momentum without doing work, while the accelerating electric field changes its kinetic energy. ATLAS experiment and Compact Muon Solenoid surround collision points and reconstruct outgoing products; the accelerator itself supplies the incoming beams rather than measuring every final particle.
The ATLAS experiment is a general-purpose particle detector at the Large Hadron Collider. Layers around the collision point combine track reconstruction, electromagnetic and hadronic calorimeters, and outer muon detectors. A central solenoid and larger toroidal magnet system provide magnetic bending in different detector regions.[ref]
A charged track's curvature estimates momentum; a calorimeter measures deposited energy; outer signals help identify penetrating muons. Combining these measurements distinguishes candidate particle types and reconstructs decays. Apparent missing transverse momentum is an event balance inferred from the measured products, so detector coverage, calibration and reconstruction errors also affect it.
- Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC by ATLAS Collaboration
- Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using 4.7 fb^-1 of sqrt(s) = 7 TeV proton-proton collision data by ATLAS Collaboration
The Compact Muon Solenoid is a general-purpose particle detector at the Large Hadron Collider, commonly called the CMS experiment. Its superconducting solenoid surrounds central tracking and calorimeter systems; outer muon detectors work with the magnet's return structure.[ref]
The CMS Experiment by CMS Collaboration. Overview of detector layers and solenoidal magnetic configuration
Charged-particle bending constrains momentum, while electromagnetic and hadronic calorimeters measure deposited energy. Combining tracker, calorimeter and muon information identifies candidate collision products. Agreement among these measurements is more informative than any one image or signal; trigger selection and reconstruction efficiency must also be accounted for when inferring a production rate.
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The Large Hadron Collider (LHC) is the world's largest and most powerful particle accelerator, located at CERN (the European Organization for Nuclear Research) near Geneva, Switzerland. It spans a circumference of about 27 kilometers (approximately 17 miles) and is situated underground. The LHC is designed to collide protons and heavy ions at very high energies, enabling physicists to explore fundamental questions about the nature of matter, the forces of the universe, and the basic building blocks of existence.
