High-energy nuclear physics
Encyclopedia
High-energy nuclear physics is a field of study that examines nuclear matter in energy regimes typically
delegated to high energy physics. The primary focus of this field is the study of heavy-ion collisions.
These types of collisions at sufficient collision energies are theorized to produce the quark-gluon plasma
. In peripheral nuclear collisions
at high energies one expects to
obtain information on the electromagnetic production of leptons and mesons which are not accessible in electron-positron colliders due to their much smaller luminosities.
Previous high-energy nuclear accelerator
experiments have studied heavy-ion collisions using projectile energies of 1 GeV/nucleon up to 158 GeV/nucleon. Experiments of this type, called "fixed target" experiments, primarily accelerate a "bunch" of ions (typically around
to 
ions per bunch) to speeds approaching the speed of light
(0.999c) and smash them into a target of similar heavy ion
s. While all collision systems are interesting, great focus was applied in the late 1990s to symmetric collision systems of gold
beams on gold
targets at Brookhaven National Laboratory
's Alternating Gradient Synchrotron
(AGS) and uranium
beams on uranium
targets at CERN
's Super Proton Synchrotron
.
Currently, high-energy nuclear physics experiments are being conducted at Brookhaven National Laboratory
's Relativistic Heavy Ion Collider
(RHIC). The four primary experiments (PHENIX, STAR, PHOBOS, and BRAHMS) study collisions of highly relativistic nuclei. Unlike fixed target experiments, collider experiments steer two accelerated beams of ions toward each other at (in the case of RHIC) six interaction regions. At RHIC, ions can be accelerated (depending on the ion size) from 100 GeV/nucleon to 250GeV/nucleon. Since each colliding ion possesses this energy moving in opposite directions, the maximum energy of the collisions can achieve a center of mass
collision energy of 200GeV/nucleon for gold and 500GeV/nucleon for protons.
In the future, high-energy nuclear physics will also be conducted at CERN
's new Large Hadron Collider
that is projected to be 7 TeV for protons and 2.8TeV for gold.
delegated to high energy physics. The primary focus of this field is the study of heavy-ion collisions.
These types of collisions at sufficient collision energies are theorized to produce the quark-gluon plasma
Quark-gluon plasma
A quark–gluon plasma or quark soup is a phase of quantum chromodynamics which exists at extremely high temperature and/or density. This phase consists of asymptotically free quarks and gluons, which are several of the basic building blocks of matter...
. In peripheral nuclear collisions
Peripheral nuclear collisions
-Brief history:In 1924, Enrico Fermi, then 23 years old, submitted a paper entitled "On the Theory of Collisions Between Atoms and Elastically Charged Particles" to Zeitschrift für Physik. This paper does not appear in his "Collected Works", but it is nevertheless said that this was one of Fermi's...
at high energies one expects to
obtain information on the electromagnetic production of leptons and mesons which are not accessible in electron-positron colliders due to their much smaller luminosities.
Previous high-energy nuclear accelerator
Particle accelerator
A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...
experiments have studied heavy-ion collisions using projectile energies of 1 GeV/nucleon up to 158 GeV/nucleon. Experiments of this type, called "fixed target" experiments, primarily accelerate a "bunch" of ions (typically around
to ions per bunch) to speeds approaching the speed of lightSpeed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
(0.999c) and smash them into a target of similar heavy ion
Heavy ion
Heavy ion refers to an ionized atom which is usually heavier than helium. Heavy-ion physics is devoted to the study of extremely hot nuclear matter and the collective effects appearing in such systems, differing from particle physics, which studies the interactions between elementary particles...
s. While all collision systems are interesting, great focus was applied in the late 1990s to symmetric collision systems of gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
beams on gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
targets at 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...
's Alternating Gradient Synchrotron
Alternating Gradient Synchrotron
The Alternating Gradient Synchrotron is a particle accelerator located at the Brookhaven National Laboratory in Long Island, New York, USA....
(AGS) and uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
beams on uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
targets at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
's Super Proton Synchrotron
Super Proton Synchrotron
The Super Proton Synchrotron is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, in circumference, straddling the border of France and Switzerland near Geneva, Switzerland. The SPS was designed by a team led by John Adams, director-general of what was...
.
Currently, high-energy nuclear physics experiments are being conducted at 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...
's Relativistic Heavy Ion Collider
Relativistic Heavy Ion Collider
The Relativistic Heavy Ion Collider is one of two existing heavy-ion colliders, and the only spin-polarized proton collider in the world. It is located at Brookhaven National Laboratory in Upton, New York and operated by an international team of researchers...
(RHIC). The four primary experiments (PHENIX, STAR, PHOBOS, and BRAHMS) study collisions of highly relativistic nuclei. Unlike fixed target experiments, collider experiments steer two accelerated beams of ions toward each other at (in the case of RHIC) six interaction regions. At RHIC, ions can be accelerated (depending on the ion size) from 100 GeV/nucleon to 250GeV/nucleon. Since each colliding ion possesses this energy moving in opposite directions, the maximum energy of the collisions can achieve a center of mass
Center of mass
In physics, the center of mass or barycenter of a system is the average location of all of its mass. In the case of a rigid body, the position of the center of mass is fixed in relation to the body...
collision energy of 200GeV/nucleon for gold and 500GeV/nucleon for protons.
In the future, high-energy nuclear physics will also be conducted at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
's new Large Hadron Collider
Large Hadron Collider
The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....
that is projected to be 7 TeV for protons and 2.8TeV for gold.
More information
- http://www.physics.rutgers.edu/np/group-npx.html
- http://www.physics.purdue.edu/henp/pub.html
- http://www.er.doe.gov/np/