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Relativistic Heavy Ion Collider

Relativistic Heavy Ion Collider

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The Relativistic Heavy Ion Collider (RHIC, "rick") is a heavy-ion
Ion
An ion is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge...

 collider
Collider
A collider is a type of a particle accelerator involving directed beams of particles.Colliders may either be ring accelerators or linear accelerators.-Explanation:...

 located at and operated by Brookhaven National Laboratory
Brookhaven National Laboratory
Brookhaven National Laboratory , is a United States national laboratory located in Upton, New York on Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base...

 (BNL) in Upton, New York
Upton, New York
Upton, New York is a hamlet on Long Island in the town of Brookhaven. It is the home of Brookhaven National Laboratory, and a National Weather Service station.Upton is located in Suffolk County, New York in the USA....

. By using RHIC to collide ion
Ion
An ion is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge...

s traveling at relativistic
Special relativity
Special relativity is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies"...

 speeds, physicists study the primordial form
Quark-gluon plasma
A quark–gluon plasma is a phase of quantum chromodynamics which exists at extremely high temperature and/or density. This phase consists of free quarks and gluons, which are the basic building blocks of matter...

 of matter that existed in the universe
Universe
The Universe comprises everything that physically exists, the entirety of space and time, all forms of matter and energy, and the physical laws and constants that govern them...

 shortly after the Big Bang
Big Bang
The Big Bang is the cosmological model of the initial conditions and subsequent development of the Universe that is supported by the most comprehensive and accurate explanations from current scientific evidence and observation...

, and also the structure of proton
Proton
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+...

s.

At present, RHIC is the most powerful heavy-ion collider in the world, although the LHC
LHC
LHC may refer to:* Large Hadron Collider, a particle accelerator and collider located on the Franco-Swiss border near Geneva, SwitzerlandLHC also may refer to:* La hora Chanante, a Spanish comedy television show...

 is expected to collide ions at higher energies in late 2009. It is also distinctive in its capability to collide spin
Spin (physics)
In particle physics and quantum mechanics, spin is a fundamental characteristic property of elementary particles including the force carriers , composite particles , and atomic nuclei....

-polarized proton
Proton
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+...

s.

The accelerator


RHIC is an intersecting storage ring
Storage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...

 particle accelerator
Particle accelerator
A particle accelerator is a device that uses electric fields to propel ions or charged subatomic particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator...

. Two independent rings (arbitrarily denoted as "blue" and "yellow" rings, see also the photograph) allow a virtually free choice of colliding projectile
Projectile
A projectile is any object propelled through space by the exertion of a force which ceases after launch. Although a thrown baseball could be considered a projectile, the word more often refers to a weapon...

s. The RHIC double storage ring is itself hexagon
Hexagon
In geometry, a hexagon is a polygon with six edges and six vertices. A regular hexagon has Schläfli symbol {6}.- Regular hexagon :The internal angles of a regular hexagon are all 120° and the hexagon has 720 degrees T. It has 6 rotational symmetries and 6 reflection symmetries, making up the...

ally shaped and 3834 m
Metre
The metre or meter is the basic unit of length in the International System of Units . Historically, the metre was defined by the French Academy of Sciences as the length between two marks on a platinum-iridium bar, which was designed to represent one ten-millionth of the distance from the Equator...

 long in circumference, with curved edges in which stored particles are deflected by 1,740 superconducting niobium-titanium
Niobium-titanium
Niobium-titanium is an alloy of niobium and titanium, used industrially as a type II superconductor wire for superconducting magnets...

 magnet
Magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials and attracts or repels other magnets.A permanent magnet is an object made from a...

s. The six interaction points are at the middle of the six relatively straight sections, where the two rings cross, allowing the particles to collide. The interaction points are enumerated by clock positions, with the injection point at 6 o'clock. Two interaction points are unused and left for further expansion (refer also to the RHIC Complex diagram).

A particle passes through several stages of booster
Booster
Booster may refer to:In science and technology:* Booster , a motor-generator set used for voltage regulation in direct current electrical power circuits...

s before it reaches the RHIC storage ring. The first stage for ions is the Tandem
Tandem
Tandem is a Latin adverb meaning "at length" or "finally." In English, the term was originally used for two or more draft horses harnessed one behind another as opposed to side-by-side...

 Van de Graaff
Van de Graaff
Van de Graaff can refer to the physicist Robert J. Van de Graaff or machines named in honor of the physicist. The devices include:* Van de Graaff generator* The linear particle accelerator design that bears his name....

 accelerator, while for proton
Proton
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+...

s, the 200 MeV linear accelerator (Linac) is used. As an example, gold nuclei leaving the Tandem Van de Graaff have an energy of about 1 MeV per nucleon and have an electric charge Q = +32 (32 electron
Electron
An electron is a subatomic particle that carries a negative electric charge. It has no known substructure and is believed to be a point particle. An electron has a mass that is approximately 1836 times less than that of the proton. The intrinsic angular momentum of the electron is a half integer...

s stripped from the gold atom
Atom
The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

). The particles are then accelerated by the Booster Synchrotron
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronized with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...

 to 95 MeV per nucleon, which injects the projectile now with Q = +77 into the Alternating Gradient Synchrotron
Alternating Gradient Synchrotron
The Alternating Gradient Synchrotron is a particle accelerator-collider complex located at the Brookhaven National Laboratory in Long Island, New York, USA....

 (AGS), before they finally reach 8.86 GeV per nucleon and are injected in a Q = +79 state (no electrons left) into the RHIC storage ring over the AGS-To-RHIC Transfer Line (ATR), sitting at the 6 o'clock position.

The main types of particle combinations used at RHIC are p
Proton
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+...

 + p
Proton
The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+...

, d
Deuterium
Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in of hydrogen...

 + Au
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is...

,
Cu
Copper
Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable and a freshly-exposed surface has a pinkish or peachy color...

 + Cu
Copper
Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable and a freshly-exposed surface has a pinkish or peachy color...

 and Au
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is...

 + Au
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is...

. The projectiles typically travel at a speed of 99.995% of the speed of light
Speed of light
In physics, the speed of light is a physical constant, the speed at which electromagnetic radiation, such as light, travels in free space . Its value is 299,792,458 metres per second...

 in vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty," but in reality, no volume of space can ever be perfectly empty...

. For Au + Au collision, the center-of-mass
Center of mass
The center of mass of a system of particles is a specific point where, for many purposes, the system behaves as if its mass were concentrated there. The center of mass is a function only of the positions and masses of the particles that compose the system...

 energy is typically 200 GeV (or 100 GeV per nucleon
Nucleon
In physics, a nucleon is a collective name for two baryons: the neutron and the proton. They are constituents of the atomic nucleus and until the 1960s were thought to be elementary particles. In those days their interactions defined strong interactions. Now they are known to be composite...

); a luminosity
Luminosity
Luminosity is a measurement of brightness usually denoted in Lumens.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction...

 of 2 × 1026 cm
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the current SI base unit of length. Centi is the SI prefix for a factor of...

−2 s
Second
The second , sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units base unit of time...

−1 was targeted during the planning. The current luminosity performance of the collider is 2.96 × 1026 cm−2 s−1 (Run-4). For p + p collision, Run-9 achieved center-of-mass energy of 500 GeV at February 12, 2009.

One unique characteristic of RHIC is its capability to produce polarized protons. RHIC holds the record of highest energy polarized protons. Polarized protons are injected into RHIC and preserve this state throughout the energy ramp. This is a difficult task that can only be accomplished with the aid of Siberian Snakes (a chain of solenoids and quadrupoles for aligning particles) and AC dipoles. The AC dipoles
have been also used in non-linear machine diagnostics for the first time in RHIC.

The experiments


There are four detectors at RHIC: STAR
STAR detector
The STAR detector, which stands for Solenoidal Tracker at RHIC, is one of the four experiments at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory....

 (6 o'clock, and near the ATR), PHENIX
PHENIX
Pioneering High Energy Nuclear Interactions eXperiment is one of the four experiments at the Relativistic Heavy Ion Collider located at the Brookhaven National Laboratory...

 (8 o'clock, pronounced like "phoenix
Phoenix (mythology)
The phoenix is a mythical sacred firebird which originated in the ancient mythologies mentioned in the Phoenician Mythology and the Egyptian and later the Greek Mythology.- Appearance and Abilities :...

", IPA ), PHOBOS (10 o'clock), and BRAHMS (2 o'clock). Two of them are still active, with PHOBOS having completed its operation after 2005 and Run-05, and BRAHMS after 2006 and Run-06.

Among the two larger detectors, STAR
STAR detector
The STAR detector, which stands for Solenoidal Tracker at RHIC, is one of the four experiments at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory....

 is aimed at the detection of hadron
Hadron
In particle physics, a hadron is a particle made of quarks held together by the strong force . Hadrons are either mesons or baryons...

s with its system of time projection chamber
Time projection chamber
In physics, a time projection chamber is a particle detector invented by David R. Nygren at Lawrence Berkeley Laboratory. It consists of a gas-filled cylindrical chamber with multi-wire proportional chambers as endplates...

s covering a large solid angle
Solid angle
The solid angle, Ω, is the two-dimensional angle in three-dimensional space that an object subtends at a point. It is a measure of how large that object appears to an observer looking from that point. A small object nearby may subtend the same solid angle as a larger object farther away...

 and in a conventionally generated solenoidal magnetic field
Magnetic field
Magnetic fields surround magnetic materials and electric currents and are detected by the force they exert on other magnetic materials and moving electric charges...

, while PHENIX
PHENIX
Pioneering High Energy Nuclear Interactions eXperiment is one of the four experiments at the Relativistic Heavy Ion Collider located at the Brookhaven National Laboratory...

 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
Pseudorapidity
In experimental particle physics, Pseudorapidity, , is a commonly used spatial coordinate describing the angle of a particle relative to the beam axis. It is defined as where is the angle between the particle momentum and the beam axis...

 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, investigating spin
Spin (physics)
In particle physics and quantum mechanics, spin is a fundamental characteristic property of elementary particles including the force carriers , composite particles , and atomic nuclei....

 dependence in p + p scattering
Scattering
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass. In conventional use, this also includes deviation of...

.

The spokespersons for each of the experiments are:

Current results


For a complementary discussion, see also quark-gluon plasma
Quark-gluon plasma
A quark–gluon plasma is a phase of quantum chromodynamics which exists at extremely high temperature and/or density. This phase consists of free quarks and gluons, which are the basic building blocks of matter...

.

For the experimental objective of creating and studying the quark-gluon plasma, RHIC has the unique ability to provide baseline measurements for itself. This consists of the both lower energy and also lower mass number
Mass number
The mass number , also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus. Because protons and neutrons both are baryons, the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion...

 projectile combinations that do not result in the density of 200 GeV Au + Au collisions, like the p + p and d + Au collisions of the earlier runs, and also Cu + Cu collisions in Run-5.

Using this approach, important results of the measurement of the hot QCD matter created at RHIC are:
  • Collective anisotropy, or elliptic flow. The multiplicity of the particles' bulk
    Bulk
    - Industry :*Bulk cargo*Bulk liquids*Bulk mail*Bulk material handling*Bulk purchasing- Physics :*Bulk density*Bulk modulus*In brane cosmology and M-theory, the bulk is a hypothetical higher dimensional space within which the eleven dimensions of our universe - Industry :*Bulk cargo*Bulk...

     with lower momenta
    Momentum
    In classical mechanics, momentum is the product of the mass and velocity of an object . For more accurate measures of momentum, see the section "modern definitions of momentum" on this page...

     exhibits a dependency as (pT is the transverse momentum, angle with the reaction plane). This is a direct result of the elliptic shape of the nucleus overlap region during the collision and hydrodynamical property of the matter created.

  • Jet
    Jet (particle physics)
    A jet is a narrow cone of hadrons and other particles produced by the hadronization of a quark or gluon in a particle physics or heavy ion experiment. Because of QCD confinement, particles carrying a color charge, such as quarks, cannot exist in free form. Therefore they fragment into hadrons...

     quenching.
    In the heavy ion collision event, scattering with a high transverse pT can serve as a probe for the hot QCD matter, as it loses its energy while traveling through the medium. Experimentally, the quantity RAA (A is the mass number) being the quotient of observed jet yield in A + A collisions and Nbin × yield in p + p collisions shows a strong damping with increasing A, which is an indication of the new properties of the hot QCD matter created.

  • Color glass condensate
    Color glass condensate
    The color glass condensate is an extreme type of matter theorized to exist in atomic nuclei travelling near the speed of light.According to Einstein’s theory of relativity, a high-energy nucleus appears length contracted, or compressed, along its direction of motion...

     saturation
    Saturation (chemistry)
    In chemistry, saturation has five different meanings:#In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a precipitate...

    .
    The Balitsky–Fadin–Kuraev–Lipatov (BFKL) dynamics which are the result of a resummation of large logarithmic terms in Q² for deep inelastic scattering with small Bjorken-x, saturate at a unitarity limit , with Npart/2 being the number of participant nucleons in a collision (as opposed to the number of binary collisions). The observed charged multiplicity follows the expected dependency of , supporting the predictions of the color glass condensate model. For a detailed discussion, see e.g. Kharzeev et al.; for an overview of color glass condensates, see e.g. Iancu & Venugopalan.

  • Particle ratios. The particle ratios predicted by statistical models allow the calculation of parameters such as the temperature at chemical freeze-out Tch and hadron chemical potential . The experimental value Tch varies a bit with the model used, with most authors giving a value of 160 MeV < Tch < 180 MeV, which is very close to the expected QCD phase transition value of approximately 170 MeV obtained by lattice QCD calculations (see e.g. Karsch).


While in the first years, theorists were eager to claim that RHIC has discovered the quark-gluon plasma (e.g. Gyulassy & McLarren), though the experimental groups were more careful not to jump to conclusions, citing various variables still in need of further measurement. The present results shows that the matter created is a fluid with a viscosity near the quantum limit, but is unlike a weakly interacting plasma (a widespread yet not quantitatively unfounded belief on how quark gluon plasma looks).

A recent overview of the physics result is e.g. provided by the RHIC Experimental Evaluations 2004, a community-wide effort of RHIC experiments to evaluate the current data in the context of implication for formation of a new state of matter. These results are from the first three years of data collection at RHIC.

The future



RHIC began operation in 2000 and is currently the most powerful heavy-ion collider in the world. It is expected, however, that the Large Hadron Collider (LHC)
Large Hadron Collider
The Large Hadron Collider is the world's largest and highest-energy particle accelerator intended to collide opposing particle beams of either protons at an energy of 7 TeV per particle or lead nuclei at an energy of 574 TeV per nucleus...

 of CERN
CERN
The European Organization for Nuclear Research , known as CERN , , is the world's largest particle physics laboratory, situated in the northwest suburbs of Geneva on the Franco–Swiss border, established in 1954...

, completed in 2008, will provide significantly higher energies once fully operational in autumn 2009.

However, RHIC will likely remain unique in various fields that the LHC in the present state will not be able to cover. Unlike LHC, RHIC is able to accelerate spin polarized protons, which would leave RHIC as the world's highest energy accelerator for studying spin-polarized proton structure.

Two planned upgrades should enhance the future scientific output of RHIC in these areas:
  • RHIC-II: An upgrade that will increase the luminosity by a further factor of 10, together with upgrades to the detectors STAR
    STAR detector
    The STAR detector, which stands for Solenoidal Tracker at RHIC, is one of the four experiments at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory....

     and PHENIX
    PHENIX
    Pioneering High Energy Nuclear Interactions eXperiment is one of the four experiments at the Relativistic Heavy Ion Collider located at the Brookhaven National Laboratory...

    .
  • eRHIC: Construction of a 10 GeV high intensity electron/positron beam facility, allowing electron-ion collisions. At least one new detector will have to be built to study the collisions. A recent review is given by A. Deshpande et al..


In October 2006, then Interim Director of BNL, Sam Aronson, has contested the claim in a Physics Today
Physics Today
Physics Today magazine, created in 1948, is the membership journal of the American Institute of Physics. It is provided to 130,000 members of twelve physics societies, including the American Physical Society...

 report that "Tevatron
Tevatron
Tevatron is a circular particle accelerator at the Fermi National Accelerator Laboratory in Batavia, Illinois and remains the highest energy particle collider in the world until collisions begin at the Large Hadron Collider . The Tevatron is a synchrotron that accelerates protons and antiprotons in...

 is unlikely to outlive the decade. Neither is ... the Relativistic Heavy Ion Collider
", referring to a report of the National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academy of Sciences and the United States National Academy of Engineering, carrying out most of the studies done in their names.-History:...

.

Fears among the public



Before RHIC started operation, there were fears among the public that the extremely high energy could produce one of the following catastrophic scenarios:
  • RHIC creates a black hole
    Black hole
    In general relativity, a black hole is a region of space in which the gravitational field is so powerful that nothing, not even light, can escape. The black hole has a one-way surface, called an event horizon, into which objects can fall, but out of which nothing can come...

  • RHIC creates a transition
    Transition
    Transition or transitional may refer to:-General:* Transition * Transition: an operation of a finite-state machine* Transition function* Transition , made by Terrafugia* The University Transition Program...

     into a different quantum mechanical
    Quantum mechanics
    Quantum mechanics is a set of principles describing the physical reality at the atomic level of matter and the subatomic . These descriptions include the simultaneous wave-like and particle-like behavior of both matter and radiation...

     vacuum
    Vacuum
    In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty," but in reality, no volume of space can ever be perfectly empty...

     (see false vacuum
    False vacuum
    In quantum field theory, a false vacuum is a metastable sector of space which appears to be a perturbative vacuum but is unstable to instanton effects which may tunnel to a lower energy state. This tunneling can be caused by quantum fluctuations or the creation of high energy particles...

    )
  • RHIC creates strange matter
    Strange matter
    Strange matter is a particular form of quark matter, usually thought of as a 'liquid' of up, down, and strange quarks. It is to be contrasted with nuclear matter, which is a liquid of neutrons and protons , and with non-strange quark matter, which is a quark liquid containing only up and down quarks...

     that is more stable than ordinary matter
    Matter
    The term matter traditionally refers to the substance that all objects are made of. One common way to identify this "substance" is through its physical properties; a common definition of matter is anything that has mass and occupies a volume...



These hypothetical theories are complex, but they predict that at least the Earth
Earth
Earth is the third planet from the Sun. It is the fifth largest of the eight planets in the solar system, and the largest of the terrestrial planets in the Solar System in terms of diameter, mass and density...

 would be destroyed within seconds, to years, to millennia, depending on the theories. However, the fact that objects of the Solar System (e.g., the Moon
Moon
The Moon is Earth's only natural satellite and the fifth largest satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is , about thirty times the diameter of the Earth. The common centre of mass of the system is located at about —a quarter the Earth's...

) have been bombarded with cosmic particles
Cosmic ray
Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, almost 10% are helium nuclei , and slightly under 1% are heavier elements and electrons...

 of significantly higher energies than that of RHIC for billions of years, without any harm to the Solar System, were among the most striking arguments that these hypotheses were unfounded.

The other main controversial issue was a demand by critics for physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

s to reasonably exclude the probability
Probability
Probability is a way of expressing knowledge or belief that an event will occur or has occurred. In mathematics the concept has been given an exact meaning in probability theory, that is used extensively in such areas of study as mathematics, statistics, finance, gambling, science, and philosophy...

 for such a catastrophic scenario. Physicists are unable to demonstrate experimental and astrophysical
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects such as galaxies, stars, planets, exoplanets, and the interstellar medium, as well as their...

 constraints of zero probability of catastrophic events, nor that tomorrow Earth will be struck with a "doomsday
Doomsday event
A doomsday event is a specific plausibly verifiable or hypothetical occurrence which has an exceptionally destructive effect on the human race. The final outcomes of doomsday events may range from a major disruption of human civilization, to the extinction of human life, to the destruction of the...

" cosmic ray
Cosmic ray
Cosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are protons, almost 10% are helium nuclei , and slightly under 1% are heavier elements and electrons...

 (they can only calculate an upper limit for the likelihood). The result would be the same destructive scenarios described above, although obviously not caused by humans. According to this argument of upper limits, RHIC would still modify the chance for the Earth's survival by an infinitesimal amount.

Concerns were raised in connection with the RHIC particle accelerator, both in the media and in the scientific community. The risk of a doomsday scenario was indicated by Martin Rees, with respect to the RHIC, as being at least a 1 in 50,000,000 chance. With regards to the production of strangelets, Frank Close
Frank Close
Francis Edwin Close OBE is a noted particle physicist who is currently Professor of Physics at the University of Oxford and a Fellow of Exeter College, Oxford.-Early life:...

, professor of physics at the University of Oxford
University of Oxford
The University of Oxford , located in the UK city of Oxford, is the oldest surviving university in the English-speaking world and is regarded as one of the world's leading academic institutions. Although the exact date of foundation remains unclear, there is evidence of teaching there as far back...

, indicates that "the chance of this happening is like you winning the major prize on the lottery 3 weeks in succession; the problem is that people believe it is possible to win the lottery 3 weeks in succession." After detailed studies, scientists reached such conclusions as "beyond reasonable doubt, heavy-ion experiments at RHIC will not endanger our planet" and that there is "powerful empirical evidence against the possibility of dangerous strangelet production."

The debate started in 1999 with an exchange of letters in Scientific American
Scientific American
Scientific American is a popular science magazine published since August 28, 1845, which according to the magazine makes it the oldest continuously published magazine in the United States...

 between Walter L. Wagner, and F. Wilczek
Frank Wilczek
Frank Anthony Wilczek is a theoretical physicist from the United States and a Nobel laureate. He is currently the Herman Feshbach Professor of Physics at the Massachusetts Institute of Technology.Wilczek, along with David Gross and H...

, Institute for Advanced Study
Institute for Advanced Study
The Institute for Advanced Study, located in Princeton, New Jersey, United States, is a center for theoretical research and intellectual inquiry. The Institute is perhaps best known as the academic home of Albert Einstein, John von Neumann, and Kurt Gödel, after their immigration to the United...

, in response to a previous article by M. Mukerjee. The media attention unfolded with an article in U.K.
United Kingdom
The United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...

 Sunday Times
The Sunday Times (UK)
The Sunday Times is a Sunday broadsheet newspaper, distributed in the United Kingdom. The Sunday Times is published by Times Newspapers Ltd, a subsidiary of News International, which is in turn owned by News Corporation. Times Newspapers also owns The Times, but the two papers were founded...

 of July 18, 1999 by J. Leake, closely followed by articles in the U.S. media. The controversy mostly ended with the report of a committee
Committee
A committee is a type of small deliberative assembly that is usually intended to remain subordinate to another, larger deliberative assembly—which when organized so that action on committee requires a vote by all its entitled members, is called the "Committee of the Whole"...

 convened by the director
Board of directors
A board of directors is a body of elected or appointed members who jointly oversee the activities of a company or organization. The body sometimes has a different name, such as board of trustees, board of governors, board of managers, or executive board...

 of Brookhaven National Laboratory, J. H. Marburger
John Marburger
Dr. John Harmen Marburger, III is an American physicist who was the Science Advisor to the President and the Director of the Office of Science and Technology Policy in the administration of President George W. Bush.-Biography:...

, ostensibly ruling out the catastrophic scenarios depicted. However, the report left open the possibility that relativistic cosmic ray impact products might behave differently while transiting earth compared to "at rest" RHIC products; and the possibility that the qualitative difference between high-E proton collisions with earth or the moon might be different than Gold on Gold collisions at the RHIC. Wagner tried subsequently to stop full energy collision at RHIC by filing Federal
Federal government of the United States
The federal government of the United States is the central government entity established by the United States Constitution, which shares sovereignty over the United States with the governments of the individual U.S. states. The federal government has three branches: the legislative, executive, and...

 lawsuits in San Francisco and New York
New York
New York is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous. The state is bordered by New Jersey and Pennsylvania to the south, and Connecticut, Massachusetts and Vermont to the east...

, but without success. The New York suit was dismissed on the technicality that the San Francisco suit was the preferred forum. The San Francisco suit was dismissed, but with leave to refile if additional information was developed and presented to the court.

On March 17, 2005, the BBC
BBC
The British Broadcasting Corporation, usually referred to by its abbreviation as the "BBC", is the longest established and largest broadcaster in the world...

 published an article implying that researcher Horaţiu Năstase
Horatiu Nastase
Horaţiu Năstase is a Romanian physicist and professor in the High energy physics group at Brown University in Providence, RI, USA.He was born in Bucharest, Romania and finished high school at Nicolae Bălcescu High School . He did his undergraduate studies in the Physics Department of the University...

 believes black holes have been created at RHIC. However, the original papers of H. Năstase and the New Scientist
New Scientist
New Scientist is a weekly international science magazine and website covering recent developments in science and technology for a general English-speaking audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of Reed Elsevier. New Scientist has maintained a...

 article cited by the BBC state that the correspondence of the hot dense QCD matter
QCD matter
Quark matter or QCD matter refers to any of a number of theorized phases of matter whose degrees of freedom include quarks and gluons...

 created in RHIC to a black hole is only in the sense of a correspondence of QCD
Quantum chromodynamics
In theoretical physics, Quantum chromodynamics is a theory of the strong interaction , a fundamental force describing the interactions of the quarks and gluons making up hadrons . It is the study of the SU Yang–Mills theory of color-charged fermions...

 scattering in Minkowski space
Minkowski space
In physics and mathematics, Minkowski space is the mathematical setting in which Einstein's theory of special relativity is most conveniently formulated. In this setting the three ordinary dimensions of space are combined with a single dimension of time to form a four-dimensional manifold for...

 and scattering in the AdS5 × X5 space in AdS/CFT; in other words, it is similar mathematically. Therefore, RHIC collisions might be useful to study quantum gravity
Quantum gravity
Quantum gravity is the field of theoretical physics attempting to unify quantum mechanics with general relativity in a self-consistent manner, or more precisely, to formulate a self-consistent theory which reduces to ordinary quantum mechanics in the limit of weak gravity and which reduces to...

 behavior within AdS/CFT, but the described physical phenomena are not the same.

Financial information


The RHIC project is sponsored by the United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...

, Office of Science
Science
Science is in its broadest sense to any systematic knowledge-base or prescriptive practice that is capable of resulting in a prediction or predictable type of outcome...

, Office of Nuclear Physics
Nuclear physics
Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei.The most commonly known applications of nuclear physics are nuclear power and nuclear weapons, but the research has provided wider applications, including those in medicine , materials...

. It had a line-item budget of 616.6 million U.S. dollars. The annual operational budgets were:
  • fiscal year 2005: 131.6 million U.S. dollars
  • fiscal year 2006: 115.5 million U.S. dollars
  • fiscal year 2007, requested: 143.3 million U.S. dollars

The total investment by 2005 is approximately 1.1 billion U.S. dollars. Though operation under the fiscal year 2006 federal budget cut was uncertain, a key portion of the operational cost (13 million U.S. dollars) was contributed privately by a group close to Renaissance Technologies
Renaissance Technologies
Renaissance Technologies is a hedge fund management company. Started in 1982 by James Simons, Renaissance currently has approximately $20 billion in assets under management...

 of East Setauket, New York.

RHIC in fiction

  • The novel Cosm (ISBN 0-380-79052-1) by the American author Gregory Benford
    Gregory Benford
    Gregory Benford is an American science fiction author and astrophysicist who is on the faculty of the Department of Physics and Astronomy at the University of California, Irvine....

     takes place at RHIC. The science fiction
    Science fiction
    Science fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically-established or scientifically-postulated laws of nature...

     setting describes the main character Alicia Butterworth, a physicist at the BRAHMS experiment, and a new universe
    Universe
    The Universe comprises everything that physically exists, the entirety of space and time, all forms of matter and energy, and the physical laws and constants that govern them...

     being created in RHIC by accident, while running with uranium
    Uranium
    Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92. Besides its 92 protons, a uranium nucleus can have between 141 and 146 neutrons. The most common uranium isotopes are U-238 and U-235 . A uranium atom has...

     ions.

  • The zombie apocalypse
    Zombie apocalypse
    The zombie apocalypse is a particular scenario of apocalyptic fiction that customarily has a science fiction/horror rationale. In a zombie apocalypse, a widespread rise of zombies hostile to human life engages in a general assault on civilization. Victims of zombies may become zombies themselves...

     novel The Rising
    The Rising (novel)
    The Rising is the first book in a series of zombie-themed horror novels written by author Brian Keene. This title won the Bram Stoker Award for Best First Novel in 2003. The Rising was optioned for both film and video game adaptation in 2004....

    by the American author Brian Keene
    Brian Keene
    Brian Keene is an author, primarily of horror and crime fiction. Keene has often been credited with ushering in the new era of zombie popularity in pop culture . -Biography:Brian Keene was born in 1967...

     referenced the media concerns of activating the RHIC raised by the article in The Sunday Times
    The Sunday Times (UK)
    The Sunday Times is a Sunday broadsheet newspaper, distributed in the United Kingdom. The Sunday Times is published by Times Newspapers Ltd, a subsidiary of News International, which is in turn owned by News Corporation. Times Newspapers also owns The Times, but the two papers were founded...

     of July 18, 1999 by J. Leake,. As revealed very early in the story, side effects of the collider experiments of the RHIC (located at "Havenbrook National Laboratories") were the cause of the zombie uprising in the novel and its sequel City of the Dead
    City of the Dead (novel)
    City of the Dead by Brian Keene was first published in 2005, it is the sequel to The Rising.-Plot description:The dead are mysteriously turning to life, becoming violent, hateful beings, possessed by demons...

    .


External links