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Interactions - Particle physics glossary
Category: Sciences > Particle Physics
Date & country: 15/01/2011, UK
Words: 55

ab (atobarn)
10-18 barns. A unit used to measure cross-section. The inverse of this unit is used to measure integrated luminosity.

The generic term for an anti-matter partner of a particle.

The anti-matter partner of the proton.

The anti-matter partner of the quark.

A hadron composed of three quarks. Examples include the protons and neutrons found in ordinary nuclei.

Beijing Electron Positron Collider

A proposed experiment to take place at the Fermilab Tevatron. It would study B-Meson decay in detail. For more information see

charmed particle
Any particle that contains the exotic charmed (c) quark is known as a charmed particle.

This experiment is based at the CESR accelerator. It is most noted for its study of the B-meson system. For more information see

(Compact Muon Solenoid)

A property of quarks and gluons. Gluons can exchange color between quarks and other gluons. This process is the origin of the strong force. It has nothing to do with the color perceived by the human eye.

coupling constant
The parameter that describes the strength of a given force.

CP violation
CP is a symmetry that relates particles to anti-particles. CP violation occurs when there is a difference in the way that particles and anti-particles interact. It is believed to be necessary for the excess of matter over antimatter we observe in the universe. This phenomenon is currently being studied in detail at BaBar and BELLE.

DOE (Department of Energy)
One of the principal federal agencies supporting research in the physical sciences in the United States. Through its Office of Science it provides approximately 90% of the support for High Energy and Nuclear Physics.

eV (electron volt)
A unit of energy equal to the amount kinetic energy an electron gains after being accelerated through an electric potential of 1 Volt. It can also be used as a unit of mass by applying Einstein's relation E=mc2.

fb (femtobarn)
10-15 barns. A unit used to measure cross-section. The inverse of this unit is used to measure integrated luminosity.

The term for a particle with half-integer spin. Examples include the quarks and leptons of the Standard Model.

galactic halo
the region of dark matter that surrounds the visible portion of a galaxy

gamma rays
photons of high energy. The most energetic forms of light are known as gamma rays.

gauge bosons
The particles that carrry the forces of the Standard Model

The generic term describing the hypothetical superpartner of any of the gauge bosons of the Standard Model.

GeV (Giga-electron Volts)
109 electron volts

The hypothetical superpartner of the gluon. The gluino has spin �.

The spin-one particle that carries the strong force.

The as-yet unobserved spin-two particle that carries gravity.

HEPAP subpanel
HEPAP appoints a subpanel every few years to have intensive and detailed discussions on specific problems. This subpanel was appointed in March 2001 to discuss the future of the particle physics program in the US as specified in the charge in Appendix B.

An experiment located at the DESY laboratory. HERA-B used the 920 GeV proton beam of HERA (data acquisition until 2003). For more information see http

Higgs boson (H)
An as yet undiscovered particle that appears when sufficient energy is imparted to the Higgs Field.

A former gold-mine located in South Dakota that is the proposed site of a National Underground Sciences Laboratory. This mine also contained the experiment that first detected solar neutrinos.

This is the name for a meson that contains the exotic strange (s) quark and either an up or down quark. These particles are also known as Kaons.

An experiment that searches for a rare decay of uncharged K-mesons into neutral pions. This decay provides valuable information about the CKM Mixing Matrix and CP violation. Further information can be found at

This experiment aims a neutrino beam from the KEK accelerator to the SuperKamiokande detector. It is searching for neutrino oscillations. For more information see

See K-Meson.

This figure of merit for an accelerator quantifies the intensity of the beams. It is directly related to the number of events produced at the machine.

A hadron composed of a quark and an anti-quark.

MeV (Mega-electron Volts)
106 electron volts

mixing angles
A particle of a given flavor sometimes transforms into a similar particle of a different flavor. The parameters that quantify how likely this is to occur are known as mixing angles.

Nuclear Science Advisory Committee that reports to the DOE (Department of Energy) and the National Science Foundation.

NSF (National Science Foundation)
One of the principal federal agencies supporting research in the physical sciences in the United States. Through its Division of Physics it provides approximately 30% of the support of the university High Energy Physics program.

p-p collisions
Collisions between two protons.

PAC (Physics Advisory Committee)
Each accelerator laboratory has a PAC to conduct rigorous reviews on proposed experiments and advise the laboratory director on the laboratory's program.

pb (picobarn)
10-12 barns. A unit used to measure cross-section. The inverse of this unit is used to measure integrated luminosity.

The gauge boson that mediates the force of electromagnetism. The photon is the quantum of light.

QCD (Quantum Chromodynamics)
The theory of the strong interaction. It describes the exchange of gluons between quarks.

quantum dimensions
As yet undiscovered dimensions of space-time that convert force particles to matter particles and vice versa. Such dimensions are predicted in theories with supersymmetry or superstrings. The pair of particles that are converted into each other are called superpartners.

One of the fundamental constituents of matter. These particles posses spin �. They come in six flavors

(Scientific Assessment Group for Experiments in Non-Accelerator Physics) A committee that reports to the Department of Energy and National Science Foundation.

the superpartner of a fermion

See Special Relativity.

The hypothetical spin-zero superpartner of the quark.

see superparticle.

A trillion floating point operations per seconds.

TeV (Tera-electron Volts)
1012 electron volts

(Weakly Interacting Massive Particle)

A gauge boson with no electric charge. It mediates the weak neutral current. It was studied in spectacular detailed by experiments at LEP and the SLC.