Editing Relativistic Heavy Ion Collider (section)

{{Short description|Particle accelerator at Brookhaven National Laboratory in Upton, New York, USA}}
{{Infobox particle accelerator
| name           = Relativistic Heavy Ion Collider (RHIC)
| image          = A section of Relativistic Heavy Ion Collider.jpg
| caption        = The Relativistic Heavy Ion Collider at [[Brookhaven National Laboratory]]. 
| type           = [[synchrotron]]
| beam           = polarized p to U ion
| target         = [[collider]]
| energy         = 255&nbsp;GeV per beam (p), 100&nbsp;GeV/nucleon per beam (Au ions)
| current        =
| brightness     =
| luminosity     = {{val|2.45e32|up=cm<sup>2</sup>⋅s}} (p+p), {{val|1.55e28|up=cm<sup>2</sup>⋅s}} (Au+Au)
| length         =
| radius         =
| circumference  = {{val|3834|u=m}}
| location       = [[Upton, New York]]
| coordinates    = {{Coord|40|53|2|N|72|52|33|W|region:US-NY_type:landmark|display=title,inline}}
| institution    = [[Brookhaven National Laboratory]]
| dates          = 2000—2025
| preceded       =
| succeeded      = 
}}

The '''Relativistic Heavy Ion Collider''' ('''RHIC''' {{IPAc-en|ˈ|r|ɪ|k}}) is the first and one of only two operating heavy-[[ion]] [[collider]]s, and the only [[Spin polarization|spin-polarized]] [[proton]] collider ever built. Located at [[Brookhaven National Laboratory]] (BNL) in [[Upton, New York]], and used by an international team of researchers, it is the only operating particle collider in the US.<ref name=Harrison2003>
{{cite journal
 |author=M. Harrison
 |author2=T. Ludlam
 |author3=S. Ozaki
 |date=2003
 |title=RHIC Project Overview
 |journal=[[Nuclear Instruments and Methods in Physics Research A]]
 |volume=499 |issue=2&ndash;3 |page=235
 |bibcode=2003NIMPA.499..235H
 |doi=10.1016/S0168-9002(02)01937-X
|url=https://zenodo.org/record/1259915
 }}</ref><ref>
{{cite journal
 |author=M. Harrison
 |author2=S. Peggs
 |author3=T. Roser
 |date=2002
 |title=The RHIC Accelerator
 |journal=[[Annual Review of Nuclear and Particle Science]]
 |volume=52 |page=425
 |bibcode=2002ARNPS..52..425H
 |doi=10.1146/annurev.nucl.52.050102.090650| doi-access=free
 }}</ref><ref>
{{cite journal
 |author=E. D. Courant
 |date=2003
 |title=Accelerators, Colliders, and Snakes
 |journal=[[Annual Review of Nuclear and Particle Science]]
 |volume=53 |page=1
 |bibcode=2003ARNPS..53....1C
 |doi=10.1146/annurev.nucl.53.041002.110450
|doi-access=free
 }}</ref> By using RHIC to collide [[ion]]s traveling at [[special relativity|relativistic]] speeds, physicists study the [[quark–gluon plasma|primordial form]] of matter that existed in the [[universe]] shortly after the [[Big Bang]].<ref>
{{cite journal
 |author=M. Riordan
 |author2=W. A. Zajc
 |date=2006
 |title=The First Few Microseconds
 |journal=[[Scientific American]]
 |volume=294 |issue=5 |pages=34A, 35–41
 |doi=10.1038/scientificamerican0506-34A
|pmid=16708486
 |bibcode=2006SciAm.294e..34R}}</ref><ref>
{{cite web
 |author=S. Mirsky
 |author2=W. A. Zajc
 |author3=J. Chaplin
 |date=26 April 2006
 |title=Early Universe, Benjamin Franklin Science, Evolution Education
 |url=http://www.scientificamerican.com/podcast/episode.cfm?id=000F3F76-D5E6-144E-95E683414B7F0000
 |work=Science Talk
 |publisher=Scientific American
 |access-date=2010-02-16
}}</ref> 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, with nucleon energies for collisions reaching 100 GeV for gold ions and 250 GeV for protons.<ref>{{Cite web |date=2022-04-29 |title=NP Relativistic Heavy Ion Collid... {{!}} U.S. DOE Office of Science (SC) |url=https://science.osti.gov/np/Facilities/User-Facilities/RHIC |access-date=2023-03-16 |website=science.osti.gov |language=en-US}}</ref> As of November 7, 2010, the [[Large Hadron Collider|Large Hadron Collider (LHC)]] has collided heavy ions of lead at higher energies than RHIC.<ref>
{{cite press release
 |date=8 November 2010
 |title=CERN Completes Transition to Lead-Ion Running at the LHC
 |url=http://press.cern/press-releases/2010/11/cern-completes-transition-lead-ion-running-lhc
 |publisher=[[CERN]]
 |access-date=2016-11-23
}}</ref> The LHC operating time for ions (lead–lead and lead–proton collisions) 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&nbsp;MeV (4&nbsp;terakelvin or 7 trillion degrees Fahrenheit) 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]].<ref>
{{cite web
 |author=A. Trafton
 |date=9 February 2010
 |title=Explained: Quark gluon plasma
 |url=http://web.mit.edu/newsoffice/2010/exp-quark-gluon-0609.html
 |publisher=[[MITnews]]
 |access-date=2017-01-24
}}</ref>

In January 2020, the US Department of Energy Office of Science selected the eRHIC design for the future [[electron–ion collider|Electron–Ion collider]] (EIC), building on the existing RHIC facility at BNL.

RHIC will cease to operate in 2025.<ref>{{Cite web |date=2025-03-28 |title=Relativistic Heavy Ion Collider enters its final chapter: 25 years of groundbreaking discoveries |url=https://www.innovationnewsnetwork.com/relativistic-heavy-ion-collider-enters-its-final-chapter-25-years-of-groundbreaking-discoveries/56806/ |url-status=live |archive-url=https://web.archive.org/web/20250331104323/https://www.innovationnewsnetwork.com/relativistic-heavy-ion-collider-enters-its-final-chapter-25-years-of-groundbreaking-discoveries/56806/ |archive-date=2025-03-31 |website=Innovation News Network}}</ref>