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quark

Contents

Contents

Idea

Quarks (Gell-Mann 64, Zweig 64) are one of the fundamental particles/matter fields in the standard model of particle physics. Quarks couple to the Yang-Mills theory given by QCD.

Quarks come in three generations of fermions:

flavors of fundamental particles – table

flavors of fermions in the
standard model of particle physics
generation of fermions1st generation2nd generation3d generation
quarks
up-typeup quarkcharm quarktop quark
down-typedown quarkstrange quarkbottom quark
leptons
chargedelectronmuontauon
neutralelectron neutrinomuon neutrinotau neutrino

At room-temperature quarks always form bound states to hadrons. This phenomenon of confinement is quantitatively well-reproduced by lattice QCD computations (see Fodor-Hoelbling 12) and qualitatively well reproduced by conceptual arguments such as the AdS/QCD correspondence, but a full analytic proof of confinement from a rigorous AQFT-like foundation of QCD remains open, see the mass gap problem.

However, at high temperature QCD goes through a deconfinement phase transition and enters another phase of matter known as the quark-gluon plasma. As the name suggests, here quarks and gluons are free.

References

General

Textbooks:

History

The quark model was proposed independently in 1964 by

  • Murray Gell-Mann, A Schematic Model of Baryons and Mesons, Phys.Lett. 8 (1964) 214-215 (spire:11880, doi:10.1016/S0031-9163(64)92001-3)

  • George Zweig, An SU(3) model for strong interaction symmetry and its breaking, version 1 is CERN preprint 8182/TH.401, Jan. 17, 1964, version 2 in Developments in the Quark Theory of Hadrons Volume 1. Edited by D. Lichtenberg and S. Rosen. Nonantum, Mass., Hadronic Press, 1980. pp. 22-101 (spire:4674)

Review of this history:

Ab-initio lattice computation

Due to confinement, before the quark-gluon plasma was seen in experiment it was a logical possibility that the quark-model of QCD is not actually correct. But more recend ab-initio computation in lattice QCD show that starting with the quark model, at least the light hadron bound states observes in experiment are reproduced by these ab-initio computations. This is discussed in the following references, see the good review Fodor-Hoelbling 12

  • S. Durr, Z. Fodor, J. Frison, C. Hoelbling, R. Hoffmann, S.D. Katz, S. Krieg, T. Kurth, L. Lellouch, T. Lippert, K.K. Szabo, G. Vulvert,

    Ab-initio Determination of Light Hadron Masses,

    Science 322:1224-1227,2008 (arXiv:0906.3599)

  • Zoltan Fodor, Christian Hoelbling, Light Hadron Masses from Lattice QCD, Rev. Mod. Phys. 84, 449, (arXiv:1203.4789)

  • S. Aoki et. al. Review of lattice results concerning low-energy particle physics (arXiv:1607.00299)

See also

Last revised on November 15, 2019 at 07:04:37. See the history of this page for a list of all contributions to it.