nLab
quark

Contents

Context

Fields and quanta

field (physics)

standard model of particle physics

force field gauge bosons

scalar bosons

matter field fermions (spinors, Dirac fields)

flavors of fundamental fermions in the
standard model of particle physics:
generation of fermions1st generation2nd generation3d generation
quarks (qq)
up-typeup quark (uu)charm quark (cc)top quark (tt)
down-typedown quark (dd)strange quark (ss)bottom quark (bb)
leptons
chargedelectronmuontauon
neutralelectron neutrinomuon neutrinotau neutrino
bound states:
mesonspion (udu d)
rho-meson (udu d)
omega-meson (udu d)
kaon (q u/dsq_{u/d} s)
eta-meson (u u + d d + s s)
B-meson (qbq b)
baryonsproton (uud)(u u d)
neutron (udd)(u d d)

(also: antiparticles)

effective particles

hadron (bound states of the above quarks)

solitons

minimally extended supersymmetric standard model

superpartners

bosinos:

sfermions:

dark matter candidates

Exotica

auxiliary fields

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 March 26, 2020 at 13:46:26. See the history of this page for a list of all contributions to it.