The puzzle of the π-> γγ* transition form factor

Details The puzzle of the π-> γγ* transition form factor The puzzle of the π-> γγ* transition form factor

2011-10-10

arxiv.org/abs/1110.2080v2

J. Phys. G39: 045003, 2012

Physics

High Energy Physics

High Energy Physics - Phenomenology

8 pages

Scientific paper

10.1088/0954-3899/39/4/045003

We study the $P\to\gamma\,\gamma^*$ ($P=\pi^0,\eta,\eta'$) transition form factors by means of the local-duality (LD) version of QCD sum rules. For the case of $\eta$ and $\eta'$, the conventional LD model provides a good description of the existing data. However, for the $\pi$ form factor we find disagreement with recent BaBar results for high $Q^2$ even though the accuracy of the LD approximation is expected to increase with $Q^2$. It remains mysterious why the $\eta$ and $\eta'$ form factors to virtual photons, on the one hand, and the $\pi$ form factor, on the other hand, show a qualitatively different behaviour corresponding to a rising with $Q^2$ violation of local duality in the pion case. In a quantum mechanical example we show that, for a bound-state size of about 1 fm, the LD sum rule provides an accurate prediction for the form factor for $Q^2\ge$ a few GeV$^2$.

Affiliated with

Also associated with

No associations

Rating

The puzzle of the π-> γγ* transition form factor does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The puzzle of the π-> γγ* transition form factor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The puzzle of the π-> γγ* transition form factor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-147486