"QCD" redirects here. For other uses, see QCD (disambiguation).
Standard Model of particle physics
Elementary particles of the Standard Model
Background
Particle physics Standard Model Quantum field theory Gauge theory Spontaneous symmetry breaking Higgs mechanism
Constituents
Electroweak interaction Quantum chromodynamics CKM matrix Standard Model mathematics
Limitations
Strong CP problem Hierarchy problem Neutrino oscillations Physics beyond the Standard Model
Scientists
Rutherford
Thomson
Chadwick
Bose
Sudarshan
Davis Jr
Anderson
Fermi
Dirac
Feynman
Rubbia
Gell-Mann
Kendall
Taylor
Friedman
Powell
Anderson
Glashow
Iliopoulos
Lederman
Maiani
Meer
Cowan
Nambu
Chamberlain
Cabibbo
Schwartz
Perl
Majorana
Weinberg
Lee
Ward
Salam
Kobayashi
Maskawa
Mills
Yang
Yukawa
't Hooft
Veltman
Gross
Pais
Pauli
Politzer
Reines
Schwinger
Wilczek
Cronin
Fitch
Vleck
Higgs
Englert
Brout
Hagen
Guralnik
Kibble
de Mayolo
Lattes
Zweig
v
t
e
In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called color. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of experimental evidence for QCD has been gathered over the years.
QCD exhibits three salient properties:
Color confinement. Due to the force between two color charges remaining constant as they are separated, the energy grows until a quark–antiquark pair is spontaneously produced, turning the initial hadron into a pair of hadrons instead of isolating a color charge. Although analytically unproven, color confinement is well established from lattice QCD calculations and decades of experiments.[1]
Asymptotic freedom, a steady reduction in the strength of interactions between quarks and gluons as the energy scale of those interactions increases (and the corresponding length scale decreases). The asymptotic freedom of QCD was discovered in 1973 by David Gross and Frank Wilczek,[2] and independently by David Politzer in the same year.[3] For this work, all three shared the 2004 Nobel Prize in Physics.[4]
Chiral symmetry breaking, the spontaneous symmetry breaking of an important global symmetry of quarks, detailed below, with the result of generating masses for hadrons far above the masses of the quarks, and making pseudoscalar mesons exceptionally light. Yoichiro Nambu was awarded the 2008 Nobel Prize in Physics for elucidating the phenomenon in 1960, a dozen years before the advent of QCD. Lattice simulations have confirmed all his generic predictions.
^J. Greensite (2011). An introduction to the confinement problem. Springer. ISBN 978-3-642-14381-6.
^
D.J. Gross; F. Wilczek (1973). "Ultraviolet behavior of non-abelian gauge theories". Physical Review Letters. 30 (26): 1343–1346. Bibcode:1973PhRvL..30.1343G. doi:10.1103/PhysRevLett.30.1343.
In theoretical physics, quantumchromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles...
Quantumchromodynamics binding energy (QCD binding energy), gluon binding energy or chromodynamic binding energy is the energy binding quarks together...
is a well-established non-perturbative approach to solving the quantumchromodynamics (QCD) theory of quarks and gluons. It is a lattice gauge theory...
Quantumchromodynamics (or QCD) is the portion of the Standard Model that deals with strong interactions, and QCD vacuum is the vacuum of quantum chromodynamics...
quantumchromodynamics (also perturbative QCD) is a subfield of particle physics in which the theory of strong interactions, QuantumChromodynamics (QCD)...
Standard Model predicted. The theory of the strong interaction (i.e. quantumchromodynamics, QCD), to which many contributed, acquired its modern form in 1973–74...
of the strong nuclear force, before being abandoned in favor of quantumchromodynamics. Subsequently, it was realized that the very properties that made...
interactions between them. The strong interactions are described by quantumchromodynamics (QCD), based on "color" SU(3). The weak interactions require the...
particle physics, which brings up the following quandary: why does quantumchromodynamics (QCD) seem to preserve CP-symmetry? In particle physics, CP stands...
bound the quarks together into protons and neutrons. The theory of quantumchromodynamics explains that quarks carry what is called a color charge, although...
related to the particles' strong interactions in the theory of quantumchromodynamics (QCD). Like electric charge, it determines how quarks and gluons...
most massive nuclei, at v = 264.3 Da. The chiral condensate in quantumchromodynamics, about a factor of a thousand smaller than the above, gives a large...
_{\mu }\psi +i{\bar {\psi }}(\partial _{\mu }\Lambda )\psi } . In quantumchromodynamics, the gauge covariant derivative is D μ := ∂ μ − i g s G μ α λ α...
Quark matter or QCD matter (quantumchromodynamic) refers to any of a number of hypothetical phases of matter whose degrees of freedom include quarks...
contributed to the field of elementary particle physics, in particular to quantumchromodynamics and string theory. Together with Guido Altarelli, he introduced...
strong interaction, gluons bind quarks into groups according to quantumchromodynamics (QCD), forming hadrons such as protons and neutrons. Gluons carry...
physics and nuclear physics overlap. Particle physics, particularly quantumchromodynamics, provides the fundamental equations that describe the properties...
gluon, traversing minuscule distance among quarks, is modeled in quantumchromodynamics (QCD). EWT, QCD, and the Higgs mechanism comprise particle physics'...
include the prevailing theories of elementary particles: quantum electrodynamics, quantumchromodynamics (QCD) and particle physics' Standard Model. Non-perturbative...
This is usually associated with a gauge theory such as quantumchromodynamics, the quantum field theory of the strong interaction, and it also occurs...