Relativistic Heavy Ion Collider (RHIC)

RHIC's 2.4 mile ring has six intersection points where its two rings of accelerating magnets cross, allowing the particle beams to collide.

RHIC is a world-class scientific research facility which hundreds of physicists from around the world use to study what the universe may have looked like in the first few moments after its creation.
Upton, New York Location
2000 Start of Operations
1,053 (FY 2023) Number of Users

Description

The Relativistic Heavy Ion Collider (RHIC), at Brookhaven National Laboratory, is the only collider with dedicated running for heavy ion research (the CERN Large Hadron Collider runs heavy ions ~ one month per year), and the only polarized proton collider ever built.  RHIC collides all ion beam species from protons to Uranium at energies up to 100 GeV (Giga Electron Volts) per nucleon (250 GeV for protons).  Two concentric accelerator rings 2.4 miles in circumference containing a total of 1,700 superconducting magnets afford RHIC the capability to independently accelerate and collide different beam species and for protons, different spin polarizations.  These capabilities make RHIC the most flexible and capable collider in the world for transformative studies of extreme states of nuclear matter and the origin of the proton spin.

Science

A few microseconds after the Big Bang, the matter that filled the universe existed as a primordial fluid of quarks and gluons, called quark-gluon plasma.  After about 20 microseconds it “condensed,” forming protons and neutrons, the first complex structures in the universe.  This scientific conjecture was confirmed at RHIC with the discovery of a new extreme state of matter a “perfect” quark-gluon liquid.  The science mission of RHIC is to understand the physics underlying the remarkable properties of this new form of matter: although the interaction among its constituents is the strongest in nature, this perfect quark-gluon liquid has less resistance to flow than any material ever observed.  Particles containing heavy charm and bottom quarks, which should transparently pass through the perfect liquid according to our best theoretical understanding of its nature, interact with it so strongly that the number of them produced is suppressed by a factor of 5 relative to expectations from proton-proton collisions in which no perfect liquid is formed.  Droplets of this perfect liquid appear to violate a fundamental symmetry of nature called parity; this phenomenon may provide insights allowing scientists to probe the most fundamental aspects of the theory of the strong force, Quantum Chromodynamics.  As a result of discoveries at RHIC we now know the quark-gluon plasma existed in the early universe, however, we still know little about its properties.

Investments by the U.S. and its international partners, including a $130M contribution from Japan, transformed RHIC into a machine with unique capabilities that is now taking its first steps to precisely determine the properties of this Perfect liquid.  Recent investments include an intensity upgrade (completed in 2012, three years early and at about a tenth of the originally estimated $100M cost), an Electron Beam Ion Source (joint DOE/NASA project that extends the available beam species and provides more cost-effective operations), and new state-of-the-art particle detectors.  Physicists around the world are intensely interested in using these new capabilities to determine the properties of the Perfect Liquid in RHIC collisions.  The next discoveries at RHIC will advance knowledge and have broad impacts in nuclear physics, particle physics, astrophysics, condensed matter physics, and cosmology.