2008/03/31 by H. R. Grigoryan, Hovhannes R. Grigoryan, Anatoly Radyushkin +1
Physics and Astronomy · #Black Holes and Theoretical Physics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.77.115024
published as Phys.Rev.D77:115024,2008 · 15 pages, 5 Figures, 4 Tables. Clarifications, 1 Table and references added, typos fixed
arxiv created 2008/05/08 · openalex publication_date 2008/06/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We propose an extension of the hard-wall AdS/QCD model by including the Chern-Simons term required to reproduce the chiral anomaly of QCD. In the framework of this holographic model, we study the vertex function F_\ensuremathπ\ensuremathγ*\ensuremathγ*(Q12,Q22) which accumulates information about the coupling of the pion to two (in general virtual) photons. We calculate the slope of the form factor with one real and one slightly virtual photon and show that it is close to experimental findings. We analyze the formal limit of large virtualities and establish that predictions of the holographic model analytically (including nontrivial dependence on the ratio of photon virtualities) coincide with those of perturbative QCD calculated for the asymptotic form of the pion distribution amplitude. We also investigate the generalized vector-meson-dominance structure of F_\ensuremathπ\ensuremathγ*\ensuremathγ*(Q12,Q22) in the extended AdS/QCD model.