Belle data on the ${\pi }^0{\gamma }^{*}\gamma$ form factor: A game changer?

We extend our analysis [S. S. Agaev, V. M. Braun, N. Offen, and F. A. Porker, Phys. Rev. D 83, 054020 (2011)] of the ${\pi }^0{\gamma }^{*}\gamma$ form factor by including a comparison with the new Belle data [S. Uehara et al. (Belle Collaboration), arXiv:1205.3249]. The necessity of new precision measurements in a broad interval of momentum transfers is emphasized.

Figure 1

The pion transition form factor for the “asymptotic” (solid line), “BMS”[5] (short dashes), “holographic” (long dashes), “model II” of Ref. 3 (dash-dotted) and “flat” (dots) pion DA. The experimental data are from Ref. 1 (squares), Ref. 2 (circles), and Ref. 4 (open triangles).

Figure 2

The pion transition form factor for the model of the pion DA described in the text. The estimated theoretical uncertainty is shown by the shaded area. The experimental data are from Ref. 1 (squares) and Ref. 4 (open triangles).

Figure 3

The model of the pion DA at the scale 1 GeV used in Fig. 2 (solid line) compared to model II of Ref. 3 shown by the dash-dotted curve in Fig. 1 (dashed) and the asymptotic DA (dotted).