In the standard model of particle physics (specifically in QCD), a baryon is bound state of three quarks via the strong nuclear force. Baryons are the “heavy” types of hadrons, the other being the mesons.

Examples of hadrons are the nucleons: protons and neutrons.

Also pentaquarks are counted as baryons.


Conceptualization and computation in AdS/QCD

In the Witten-Sakai-Sugimoto model for strongly coupled QCD via an intersecting D-brane model, the hadrons in QCD correspond to string-theoretic-phenomena in an ambient bulk field theory on an approximately anti de Sitter spacetime:

  1. the mesons (bound states of 2 quarks) correspond to open strings in the bulk, whose two endpoints on the asymptotic boundary correspond to the two quarks;

  2. baryons (bound states of N cN_c quarks) appear in two different but equivalent (Sugimoto 16, 15.4.1) guises:

    1. as wrapped D4-branes with N cN_c open strings connecting them to the D8-brane

      (Witten 98b, Gross-Ooguri 98)

    2. as skyrmions

      (Sakai-Sugimoto 04, section 5.2, Sakai-Sugimoto 05, section 3.3, see Bartolini 17).

For review see Sugimoto 16, also Rebhan 14, around (18).

graphics grabbed from Sugimoto 16

This produces baryon mass spectra with moderate quantitative agreement with experiment (HSSY 07):

graphics grabbed from Sugimoto 16



See also

  • Wikipedia, Baryon

  • Aarts, Baryons at finite temperature (pdf)

In Witten-Sakai-Sugimoto model for AdS-QCD


  • Anton Rebhan, The Witten-Sakai-Sugimoto model: A brief review and some recent results, 3rd International Conference on New Frontiers in Physics, Kolymbari, Crete, 2014 (arXiv:1410.8858)

  • Shigeki Sugimoto, Skyrmion and String theory, chapter 15 in M. Rho, Ismail Zahed (eds.) The Multifaceted Skyrmion, World Scientific 2016 (doi:10.1142/9710)

Last revised on September 8, 2019 at 15:12:10. See the history of this page for a list of all contributions to it.