Altas Energías

gamma^* \gamma \rightarrow \pi^0 transition form factor - QCD confronts Experiment

by Dr. Adnan Bashir (UMSNH)

Wednesday, 6 March 2013 from to (Mexico/General)
at IF-UNAM ( Sala Sandoval Vallarta )
Description
Experiments of Babar in 2009 measured \gamma^* \gamma \rightarrow \pi^0
transition form factor and reported an ultraviolet enhamcement in 
disaccord with long standing asymptotic QCD predictions triggering a 
multitude new theoretical auggestions. Employ Schwinger-Dyson 
equations, we present a self-consistent treatments of the pion, 
which connects its static properties and elastic and transition 
form factors. The asymptotic DSE results 
employing an interaction that preserves the one-loop renormalization 
group behavior of QCD, agree with the perturbative QCD predictions 
computed in the pioneering work of Brodsky and Lepage two decades 
ago. These results are also in agreement with all the existing 
experimental data with an exception of the large-Q2 BaBar data with 
which they disagree markedly. Our analysis supports a view that the 
large-Q^2 data obtained by the BaBar-Collaboration is not an accurate 
measure of the \gamma^* \gamma \rightarrow \pi^0 form factor. Then how 
does the conflict get resolved? 
Support Email: toledo@fisica.unam.mx