Contents

# Contents

## Idea

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.

## Properties

### 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 $N_c$ quarks) appear in two different but equivalent (Sugimoto 16, 15.4.1) guises:

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

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

## References

### General

• Wikipedia, Baryon

• Aarts, Baryons at finite temperature (pdf)

### In Witten-Sakai-Sugimoto model for AdS-QCD

Review

• 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.