Anomalous Form Factor of the Neutral Pion in Extended AdS/QCD Model with Chern-Simons Term
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_{\pi \gamma^* \gamma^*}(Q_1^2,Q_2^2) 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 photons 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 with asymptotic pion wave function. We also investigate the generalized VMD structure of F_{\pi \gamma^* \gamma^*}(Q_1^2,Q_2^2) in the extended AdS/QCD model.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-060R23177
- OSTI ID:
- 955828
- Report Number(s):
- JLAB-THY-08-802; arXiv:0803.1143; DOE/OR/23177-0385; PRVDAQ; TRN: US1004766
- Journal Information:
- Physical Review D, Vol. 77; ISSN 1550-7998
- Country of Publication:
- United States
- Language:
- English
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