1206.5764 (Dmitri Melikhov et al.)

Lessons from the recent Belle measurement of the $π^0γ$
transition form factor    [PDF]

Dmitri Melikhov, Berthold Stech

The recent Belle measurement [1] allows two conclusions concerning the $\pi\gamma$ transition form factor: (i) The $\pi\gamma$ form factor extracted from the Belle data points is in very good agreement with the non-strange I=0 component of the $\eta$ and $\eta'$ form factors obtained from the BaBar measurements. (ii) Within errors, the $\pi\gamma$ form factor from Belle is compatible with the pQCD factorization theorem. Still, a better fit to the full data set of the $\pi\gamma$, $\eta\gamma$, and $\eta'\gamma$ form factors favors the small logarithmic rise $Q^2 F_{P\gamma}(Q^2)\sim \log(Q^2)$ .

View original: http://arxiv.org/abs/1206.5764