page_title: Relativistic Heavy Ion Collider
section_title: The experiments
hierarchical_section_title: Relativistic Heavy Ion Collider / The experiments
caption_attribution_description: English: A view of one of the first full-energy collisions between gold ions at Brookhaven National Laboratory's Relativistic Heavy Ion Collider, as captured by the Solenoidal Tracker At RHIC (STAR) detector. The tracks indicate the paths taken by thousands of subatomic particles produced in the collisions as they pass through the STAR Time Projection Chamber, a large, 3-D digital camera. Credit: Image courtesy of Brookhaven National Laboratory.
context_page_description: The Relativistic Heavy Ion Collider is the first and one of only two operating heavy-ion colliders, and the only spin-polarized proton collider ever built. Located at Brookhaven National Laboratory in Upton, New York, and used by an international team of researchers, it is the only operating particle collider in the US. By using RHIC to collide ions traveling at relativistic speeds, physicists study the primordial form of matter that existed in the universe shortly after the Big Bang. By colliding spin-polarized protons, the spin structure of the proton is explored.
  RHIC is as of 2019 the second-highest-energy heavy-ion collider in the world. As of November 7, 2010, the Large Hadron Collider has collided heavy ions of lead at higher energies than RHIC. The LHC operating time for ions is limited to about one month per year.
  In 2010, RHIC physicists published results of temperature measurements from earlier experiments which concluded that temperatures in excess of 345 MeV had been achieved in gold ion collisions, and that these collision temperatures resulted in the breakdown of "normal matter" and the creation of a liquid-like quark–gluon plasma.
context_section_description: There is one detector currently operating at RHIC: STAR (6 o'clock, and near the AGS-to-RHIC Transfer Line). PHENIX (8 o'clock) took last data in 2016. PHOBOS (10 o'clock) completed its operation in 2005, and BRAHMS (2 o'clock) in 2006. A new detector sPHENIX is under construction in the old PHENIX hall and is expected to being taking data in 2023.
  Among the two larger detectors, STAR is aimed at the detection of hadrons with its system of time projection chambers covering a large solid angle and in a conventionally generated solenoidal magnetic field, while PHENIX is further specialized in detecting rare and electromagnetic particles, using a partial coverage detector system in a superconductively generated axial magnetic field. The smaller detectors have larger pseudorapidity coverage, PHOBOS has the largest pseudorapidity coverage of all detectors, and tailored for bulk particle multiplicity measurement, while BRAHMS is designed for momentum spectroscopy, in order to study the so-called "small-x" and saturation physics. There is an additional experiment, PP2PP (now part of STAR), investigating spin dependence in p + p scattering.
  The spokespersons for each of the experiments are:
  STAR: Helen Caines (Yale University) and Lijuan Ruan  (Brookhaven National Laboratory)
  PHENIX: Yasuyuki Akiba  (Riken)
  sPHENIX:   Gunter Roland (MIT) and David Morrison (Brookhaven National Laboratory)
caption: A view of gold ions collisions as captured by the STAR detector.
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