Abstract
We investigate properties of baryons in a family of holographic field theories related to the Sakai-Sugimoto model of holographic QCD. Starting with the N f = 2 Sakai-Sugimoto model, we truncate to a 5D Yang-Mills action for the gauge fields associated with the noncompact directions of the flavor D8-branes. We define a free parameter γ that controls the strength of this Yang-Mills term relative to the Chern-Simons term that couples the Abelian gauge field to the SU(2) instanton density. Moving away from γ = 0 should incorporate some of the effects of taking the Sakai-Sugimoto model away from large ’t Hooft coupling λ. In this case, the baryon ground state corresponds to an oblate SU(2) instanton on the bulk flavor branes: the usual SO(4) symmetric instanton is deformed to spread more along the field theory directions than the radial direction. We numerically construct these anisotropic instanton solutions for various values of γ and calculate the mass and baryon charge profile of the corresponding baryons. Using the value γ = 2.55 that has been found to best fit the mesonic spectrum of QCD, we find a value for the baryon mass of 1.19 GeV, significantly more realistic than the value 1.60 GeV computed previously using an SO(4) symmetric ansatz for the instanton.
Article PDF
Similar content being viewed by others
References
T. Sakai and S. Sugimoto, Low energy hadron physics in holographic QCD, Prog. Theor. Phys. 113 (2005) 843 [hep-th/0412141] [INSPIRE].
T. Sakai and S. Sugimoto, More on a holographic dual of QCD, Prog. Theor. Phys. 114 (2005) 1083 [hep-th/0507073] [INSPIRE].
E. Witten, Anti-de Sitter space, thermal phase transition and confinement in gauge theories, Adv. Theor. Math. Phys. 2 (1998) 505 [hep-th/9803131] [INSPIRE].
O. Aharony, J. Sonnenschein and S. Yankielowicz, A holographic model of deconfinement and chiral symmetry restoration, Annals Phys. 322 (2007) 1420 [hep-th/0604161] [INSPIRE].
H. Hata, T. Sakai, S. Sugimoto and S. Yamato, Baryons from instantons in holographic QCD, Prog. Theor. Phys. 117 (2007) 1157 [hep-th/0701280] [INSPIRE].
D.K. Hong, M. Rho, H.-U. Yee and P. Yi, Chiral Dynamics of Baryons from String Theory, Phys. Rev. D 76 (2007) 061901 [hep-th/0701276] [INSPIRE].
D.K. Hong, M. Rho, H.-U. Yee and P. Yi, Dynamics of baryons from string theory and vector dominance, JHEP 09 (2007) 063 [arXiv:0705.2632] [INSPIRE].
A. Pomarol and A. Wulzer, Stable skyrmions from extra dimensions, JHEP 03 (2008) 051 [arXiv:0712.3276] [INSPIRE].
A. Pomarol and A. Wulzer, Baryon Physics in Holographic QCD, Nucl. Phys. B 809 (2009) 347 [arXiv:0807.0316] [INSPIRE].
A. Pomarol and A. Wulzer, Baryon physics in a five-dimensional model of hadrons, arXiv:0904.2272 [INSPIRE].
A. Cherman, T.D. Cohen and M. Nielsen, Model Independent Tests of Skyrmions and Their Holographic Cousins, Phys. Rev. Lett. 103 (2009) 022001 [arXiv:0903.2662] [INSPIRE].
D.K. Hong, M. Rho, H.-U. Yee and P. Yi, Nucleon form-factors and hidden symmetry in holographic QCD, Phys. Rev. D 77 (2008) 014030 [arXiv:0710.4615] [INSPIRE].
K. Hashimoto, T. Sakai and S. Sugimoto, Holographic Baryons: Static Properties and Form Factors from Gauge/String Duality, Prog. Theor. Phys. 120 (2008) 1093 [arXiv:0806.3122] [INSPIRE].
K.-Y. Kim and I. Zahed, Electromagnetic Baryon Form Factors from Holographic QCD, JHEP 09 (2008) 007 [arXiv:0807.0033] [INSPIRE].
A. Cherman and T. Ishii, Long-distance properties of baryons in the Sakai-Sugimoto model, Phys. Rev. D 86 (2012) 045011 [arXiv:1109.4665] [INSPIRE].
G. Panico and A. Wulzer, Nucleon Form Factors from 5D Skyrmions, Nucl. Phys. A 825 (2009) 91 [arXiv:0811.2211] [INSPIRE].
P. Colangelo, J.J. Sanz-Cillero and F. Zuo, Large-distance properties of holographic baryons, Nucl. Phys. B 875 (2013) 351 [arXiv:1306.6460] [INSPIRE].
Particle Data Group collaboration, J. Beringer et al., Review of Particle Physics (RPP), Phys. Rev. D 86 (2012) 010001 [INSPIRE].
S. Bolognesi and P. Sutcliffe, The Sakai-Sugimoto soliton, JHEP 01 (2014) 078 [arXiv:1309.1396] [INSPIRE].
E. Witten, Some Exact Multi-Instanton Solutions of Classical Yang-Mills Theory, Phys. Rev. Lett. 38 (1977) 121 [INSPIRE].
P. Forgacs and N. Manton, Space-Time Symmetries in Gauge Theories, Commun. Math. Phys. 72 (1980) 15 [INSPIRE].
M. Headrick, S. Kitchen and T. Wiseman, A new approach to static numerical relativity and its application to Kaluza-Klein black holes, Class. Quant. Grav. 27 (2010) 035002 [arXiv:0905.1822] [INSPIRE].
K. Hashimoto, T. Sakai and S. Sugimoto, Nuclear Force from String Theory, Prog. Theor. Phys. 122 (2009) 427 [arXiv:0901.4449] [INSPIRE].
N. Horigome and Y. Tanii, Holographic chiral phase transition with chemical potential, JHEP 01 (2007) 072 [hep-th/0608198] [INSPIRE].
S.-J. Sin, Gravity back-reaction to the baryon density for bulk filling branes, JHEP 10 (2007) 078 [arXiv:0707.2719] [INSPIRE].
D. Yamada, Sakai-Sugimoto model at high density, JHEP 10 (2008) 020 [arXiv:0707.0101] [INSPIRE].
O. Bergman, G. Lifschytz and M. Lippert, Holographic Nuclear Physics, JHEP 11 (2007) 056 [arXiv:0708.0326] [INSPIRE].
V. Kaplunovsky, D. Melnikov and J. Sonnenschein, Baryonic Popcorn, JHEP 11 (2012) 047 [arXiv:1201.1331] [INSPIRE].
M. Rozali, H.-H. Shieh, M. Van Raamsdonk and J. Wu, Cold Nuclear Matter In Holographic QCD, JHEP 01 (2008) 053 [arXiv:0708.1322] [INSPIRE].
Open Access
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1309.7037
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Rozali, M., Stang, J.B. & Van Raamsdonk, M. Holographic baryons from oblate instantons. J. High Energ. Phys. 2014, 44 (2014). https://doi.org/10.1007/JHEP02(2014)044
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP02(2014)044