Wednesday, February 22, 2012

1202.4471 (Dmitri Melikhov et al.)

On the $γ^*γ\toπ(η,η')$ transition form factors    [PDF]

Dmitri Melikhov, Berthold Stech
The surprising results by the BarBar collaboration on the $\pi\gamma$
transition form factor require new thoughts about the high-$Q^2$ dependence of
the form factors with virtual photons. We make use of the anomaly sum rule
which relates the hadron spectral density to the axial anomaly. We study the
quark-hadron duality relation for this sum rule and find out that the increase
of the rescaled form factor $Q^2F_{\pi\gamma}(Q^2)\sim\log(Q^2)$ suggested by
the BaBar data requires the presence of a $1/s$-correction term in the relation
between the one-loop spectral density and the hadron-continuum spectral
density.
View original: http://arxiv.org/abs/1202.4471

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