Anomalous form factor of the neutral pion in an extended AdS/QCD model with Chern-Simons term

Journal Article · Sun Jun 01 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.115024· OSTI ID:21205121

Grigoryan, H R ^[1]; Radyushkin, A V ^[2]

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1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
2. Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

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{sub {pi}}{sub {gamma}}{sub *{gamma}}{sub *}(Q{sub 1}{sup 2},Q{sub 2}{sup 2}) 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{sub {pi}}{sub {gamma}}{sub *{gamma}}{sub *}(Q{sub 1}{sup 2},Q{sub 2}{sup 2}) in the extended AdS/QCD model.

• OSTI ID: 21205121
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMPTOTIC SOLUTIONS
CHIRALITY
COUPLING
DISTRIBUTION
FORECASTING
FORM FACTORS
PHOTONS
PIONS NEUTRAL
QUANTUM CHROMODYNAMICS
SIMULATION
VECTOR MESONS
VERTEX FUNCTIONS