Low energy hadron physics in holographic QCD
Low energy hadron physics in holographic QCD
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DOI：
10.1143/ptp.113.843
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发表时间：
2004-12
影响因子：
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通讯作者：
T. Sakai;S. Sugimoto
中科院分区：
文献类型：
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作者：
T. Sakai;S. Sugimoto
我们提出了一种具有无质量味道的四维大N_c QCD的全息对偶。该模型是通过在超对称性完全被破坏的D4背景中放置N_f探针D8膜来构建的。QCD中的手征对称性破缺表现为超重力背景下D8-反D8对的光滑内插。介子谱是通过分析五维Yang-Mills理论得到的，该理论源于D8膜的非阿贝尔DBI作用。结果发现，我们的模型产生了无质量的介子，它们被认为是与手征对称破缺有关的Nambu-Goldstone玻色子。我们得到了介子场的低能有效作用量，并指出它包含了通常的手征拉格朗日动力学项和Skyrme动力学项。定义动态重子的薄膜构型被认为是天空中的重子。我们还导出了包括最轻矢量介子在内的有效作用量。我们的模型与隐藏局域对称方法中的模型密切相关，并且得到了耦合之间的Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin-type关系。此外，我们还研究了探针膜上的Chern-Simons项，发现它导致了Wess-Zumino-Witten项。我们还考虑了Eta介子的质量，从超引力出发，给出了满足Witten-Venziano公式的Eta质量项的简单推导。
We present a holographic dual of four-dimensional, large N_c QCD with massless flavors. This model is constructed by placing N_f probe D8-branes into a D4 background, where supersymmetry is completely broken. The chiral symmetry breaking in QCD is manifested as a smooth interpolation of D8 - anti-D8 pairs in the supergravity background. The meson spectrum is examined by analyzing a five-dimensional Yang-Mills theory that originates from the non-Abelian DBI action of the probe D8-brane. It is found that our model yields massless pions, which are identified with Nambu-Goldstone bosons associated with the chiral symmetry breaking. We obtain the low-energy effective action of the pion field and show that it contains the usual kinetic term of the chiral Lagrangian and the Skyrme term. A brane configuration that defines a dynamical baryon is identified with the Skyrmion. We also derive the effective action including the lightest vector meson. Our model is closely related to that in the hidden local symmetry approach, and we obtain a Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin-type relation among the couplings. Furthermore, we investigate the Chern-Simons term on the probe brane and show that it leads to the Wess-Zumino-Witten term. The mass of the \eta' meson is also considered, and we formulate a simple derivation of the \eta' mass term satisfying the Witten-Veneziano formula from supergravity.