[Jlab-seminars] Theory Center Seminar

[Mary Fox]

Theory Center Seminar
Monday, Nov. 28, 2016
1:00 p.m. (Coffee at 12:45 p.m.)
CEBAF Center, Room L102

Tomas Husek
Charles University in Prague

*Electromagnetic Transition Form Factor and Radiative Corrections**in 
Decays of Neutral Pions*

In this talk I present the two-hadron saturation (THS) scenario for the 
PVV correlator
and apply it to two important processes of the low energy hadron 
physics: the Dalitz
decay of $\pi^0$ and $\pi^0\to e^+e^-$. Experimental and theoretical 
results on the rare
decay $\pi^0\to e^+e^-$ are briefly summarized. The notorious 
$3.3\,\sigma$ discrepancy
between the SM prediction and the experimental value provided by KTeV 
collaboration is
discussed in the view of a complete set of NLO QED radiative 
corrections. The important
contribution of analytical two-loop QED corrections together with the 
bremsstrahlung
contribution beyond the soft-photon approximation are reviewed. Using 
the leading
logarithm approximation, the possible contribution of QCD corrections is 
estimated.
The discrepancy under discussion then reduces down to $1.8\,\sigma$. The 
obtained
results can also be used in a theoretical calculation of the hadronic 
light-by-light
scattering contribution to the $g-2$ type experiments.
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