Baryons In Holographic QCD Research Articles

Heavy Baryons in Holographic QCD Using Higher Dimensional Degrees of Freedom

Heavy Baryons in Holographic QCD Using Higher Dimensional Degrees of Freedom

Heavy baryons in holographic QCD with higher dimensional degrees of freedom

We try to introduce heavy flavors to Sakai-Sugimoto model by regarding higher dimensional components of gauge fields as heavy mesons. Using the Forg\'acs and Manton approach, we obtain a theory composed of heavy mesons and the instanton of light flavors. Applying the collective coordinate quantization method, we derived a mass formula of heavy baryons. In the leading order of $1/m_{H}$ expansion ($m_{H}$ the mass of a heavy quark), we find singlet and doublet states in the heavy quark symmetry (HQS). Also, we obtain the degenerate Roper like and odd parity excitations. By virtue of heavy meson degrees of freedom, our mass formula reproduces the mass ordering of $\Sigma^*_c$ and $\Lambda_c^*$ correctly.

Baryon and chiral symmetry breaking in holographic QCD

We study the relationship between chiral symmetry breaking and baryons in holographic QCD. We construct a soliton with unit baryon charge in the presence of a nonzero mean value of the scalar bifundamental field, which is dual to the chiral condensate. We obtain a relation between the chiral condensate and the mass of the baryon and find in a clear-cut way that at large values of the condensate the holographic soliton is no longer located on the IR wall. Instead it is split into two halves, which are symmetrically located on the left and right flavor branes. On the other hand we find that the local value of the quark condensate is suppressed in the core of the soliton, which is evidence for a partial chiral symmetry restoration inside the baryon.

A low-dimensional analogue of holographic baryons

Baryons in holographic QCD correspond to topological solitons in the bulk. The most prominent example is the Sakai–Sugimoto model, where the bulk soliton in the five-dimensional spacetime of AdS-type can be approximated by the flat space self-dual Yang–Mills instanton with a small size. Recently, the validity of this approximation has been verified by comparison with the numerical field theory solution. However, multi-solitons and solitons with finite density are currently beyond numerical field theory computations. Various approximations have been applied to investigate these important issues and have led to proposals for finite density configurations that include dyonic salt and baryonic popcorn. Here we introduce and investigate a low-dimensional analogue of the Sakai–Sugimoto model, in which the bulk soliton can be approximated by a flat space sigma model instanton. The bulk theory is a baby Skyrme model in a three-dimensional spacetime with negative curvature. The advantage of the lower-dimensional theory is that numerical simulations of multi-solitons and finite density solutions can be performed and compared with flat space instanton approximations. In particular, analogues of dyonic salt and baryonic popcorn configurations are found and analysed.

Massive pions, anomalies and baryons in holographic QCD

We consider a holographic model of QCD, obtained by a very simple modification of the original construction, which describes at the same time the pion mass, the QCD anomalies and the baryons as topological solitons. We study in detail its phenomenological implications in both the mesonic and baryonic sectors and compare with the observations.

Comments on baryons in holographic QCD

We generalize the description of baryons as instantons of Sakai-Sugimoto model to the case where the flavor branes are non-anti-podal. The later corresponds to quarks with a ``string endpoint mass''. We show that the baryon vertex is located on the flavor branes and hence the generalized baryons also associate with instantons. We calculate the baryon mass spectra, the isoscalar and axial mean square radii, the isoscalar and isovector magnetic moments and the axial coupling as a function of the mass scaleMKK and the location ζ of the tip of U-shaped flavor D8-branes. We determine the values of MKK and ζ from a best fit comparison with the experimental data. The later comes out to be in a forbidden region, which may indicate that the incorporation of baryons in Sakai-Sugimoto model has to be modified. We discuss the analogous baryons in a non-critical gravity model. A brief comment on the single flavor case (Nf = 1) is also made.

Properties of Baryons from D-Branes and Instantons

We give a brief summary of our recent works [H. Hata, T. Sakai, S. Sugimoto and S. Yamato, Prog. Theor. Phys. 117 (2007), 1157; hep-th/0701280. K. Hashimoto, T. Sakai and S. Sugimoto, arXiv:0806.3122] on the baryons in holographic QCD [T. Sakai and S. Sugimoto, Prog. Theor. Phys. 113 (2005), 843; hep-th/0412141; Prog. Theor. Phys. 114 (2005), 1083; hep-th/0507073]. In the holographic description, meson effective action is given by the five dimensional Yang-Mills – Chern-Simons theory in a certain curved background. The baryon is described as a soliton carrying an instanton number on the four dimensional space. By quantizing the soliton, we obtain various baryon states and calculate static quantities such as charge radii, magnetic moments, axial coupling, etc.

BARYONS WITH HOLOGRAPHY

We perform the first study of baryons in holographic QCD with [Formula: see text] multi-D-brane system in type IIA superstring theory. The baryon is described as a chiral soliton solution in the four-dimensional meson effective action derived from holographic QCD. We also present a brief review of the holographic model from the viewpoints of recent hadron physics and QCD phenomenologies.

Baryons in holographic QCD with N_f=3

Baryons in holographic QCD with N_f=3

Baryons in holographic QCD

We study baryons in holographic QCD with $\mathrm{D}4/\mathrm{D}8/\overline{\mathrm{D}8}$ multi-D-brane system. In holographic QCD, the baryon appears as a topologically nontrivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton brane-induced Skyrmion. Some review of $\mathrm{D}4/\mathrm{D}8/\overline{\mathrm{D}8}$ holographic QCD is presented from the viewpoints of recent hadron physics and QCD phenomenologies. A four-dimensional effective theory with pions and $\ensuremath{\rho}$ mesons is uniquely derived from the non-Abelian Dirac-Born-Infeld (DBI) action of D8 brane with D4 supergravity background at the leading order of large ${N}_{c}$, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and $\ensuremath{\rho}$-meson fields, we derive the energy functional and the Euler-Lagrange equation of brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the soliton solution and figure out the pion profile $F(r)$ and the $\ensuremath{\rho}$-meson profile $\stackrel{\texttildelow{}}{G}(r)$ of the brane-induced Skyrmion with its total energy, energy density distribution, and root-mean-square radius. These results are compared with the experimental quantities of baryons and also with the profiles of standard Skyrmion without $\ensuremath{\rho}$ mesons. We analyze interaction terms of pions and $\ensuremath{\rho}$ mesons in brane-induced Skyrmion, and find a significant $\ensuremath{\rho}$-meson component appearing in the core region of a baryon.

Baryons in holographic QCD(Fundamental Problems and Applications of Quantum Field Theory-Topological Aspects of Quantum Field Theory-)

Baryons in holographic QCD(Fundamental Problems and Applications of Quantum Field Theory-Topological Aspects of Quantum Field Theory-)

Brane-Induced Skyrmions

We study baryons in holographic QCD with D4/D8/\overline D8 multi D brane system. In holographic QCD, the baryon appears as a topologically non-trivial chiral soliton in a four-dimensional effective theory of mesons, which is called ‘Brane-induced Skyrmion’. We derive and calculate the Euler-Lagrange equation for the hedgehog configuration with chiral profile F(r) and ρ-meson profile \tildeG(r), and obtain the soliton solution of the holographic QCD.