Brookhaven High-Energy Physics

High-energy physicists probe the properties and behavior of the most elementary particles in the universe. At the Alternating Gradient Synchrotron (AGS), they perform experiments of unique sensitivity using high-intensity, intermediate-energy beams. The AGS currently provides the world’s most intense high-energy proton beam. It is also the world’s most versatile accelerator, accelerating protons, polarized protons, and heavy ions to near the speed of light.

Magnet system at Brookhaven used to measure the magnetic moment of the muon.

Important discoveries in high-energy physics were made at the AGS within the last decade. An international collaboration, including key physicists from Brookhaven, performed a very high-precision measurement of a property known as the “magnetic moment” of the muon, a fundamental particle, to compare it with theoretical calculations. This task would test the Standard Model of particle physics, the longstanding theory that describes the fundamental particles and forces—the weak force, the strong force, and electromagnetism—that make up all matter. In this recent face-off between experiment and theory, some physicists interpret the experimental result as the first evidence of physics beyond the Standard Model. Continued scrutiny of theory and further experiments are needed to determine if, in fact, the Standard Model must be revised, or if a new theory will take its place.

In 1997, another international team announced they had observed the rarest decay of a kaon, a composite particle composed of quarks. In 2002, researchers again detected this same rare kaon decay at the AGS, an important confirmation of the earlier discovery. Interpreted as a rate of decay, this very rare process also hints at physics beyond the Standard Model, but further experiments will be needed before this interpretation is confirmed.

Brookhaven is managing the U.S. participation in building the ATLAS detector, now under construction in Geneva, Switzerland, as one of the two principal experiments at the Large Hadron Collider (LHC) at CERN, the European laboratory for particle physics. LHC experiments will push particle physics to a new energy frontier and enable ATLAS scientists to search for hypothesized “supersymmetric” partners of known particles, as well as the Higgs particle, a manifestation of the field thought to give elementary particles their mass.

The Laboratory is also creating a Brookhaven-based computing facility for ATLAS and will manage U.S. participation in the LHC research program. In addition, Brookhaven is building superconducting magnets for the LHC accelerator rings.

> Condensed Matter Physics

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Last Modified: October 2, 2012