La cromodinámica cuántica (QCD) es una teoría cuántica de campos que describe una de las fuerzas fundamentales, la interacción fuerte. Fue propuesta a comienzos de los años 70 por David Politzer, Frank Wilczek y David Gross como teoría para entender la estructura de bariones (colectivos de tres quarks, como protones y neutrones) y mesones (pares quark-antiquark, como los piones). Por su trabajo en cromodinámica cuántica, a Gross, Wilczek y Politzer les fue concedido el Premio Nobel de Física en 2004. El nombre «cromodinámica» viene de la palabra griega chromos (color). Este nombre es oportuno ya que a la carga de los quarks, partículas básicas dentro de esta teoría, se le designa como carga de color; aunque no está relacionada con la percepción visual del color. La cromodinámica cuántica es una parte muy importante del modelo estándar de la física de partículas.

Leer el artículo completo en Wikipedia · CC-BY-SA

In theoretical physics, quantum chromodynamics (QCD) is the theory of strong interactions, a fundamental force describing the interactions between quarks and gluons which make up 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 carrier of the theory, like 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 enjoys two peculiar properties: \n* Confinement, which means that the force between quarks does not diminish as they are separated. Because of this, when you do separate a quark from other quarks, the energy in the gluon field is enough to create another quark pair; they are thus forever bound into hadrons such as the proton and the neutron or the pion and kaon. Although analytically unproven, confinement is widely believed to be true because it explains the consistent failure of free quark searches, and it is easy to demonstrate in lattice QCD. \n* Asymptotic freedom, which means that in very high-energy reactions, quarks and gluons interact very weakly creating a quark–gluon plasma. This prediction of QCD was first discovered in the early 1970s by David Politzer, Frank Wilczek and David Gross. For this work they were awarded the 2004 Nobel Prize in Physics. The phase transition temperature between these two properties has been measured by the ALICE experiment to be well above 160 MeV. Below this temperature, confinement is dominant, while above it, asymptotic freedom becomes dominant.

Leer el artículo completo en Wikipedia · CC-BY-SA