[Cuga] Theory Seminar---a message from Anatoly Radyushkin

[Rachel Harris]

Wednesday November 11th
3pm, L102/104: 
Informal Theory Cake Seminar:
Anatoly Radyushkin (ODU/JLab):

"Lava flowing over pQCD: gamma* gamma -> pi0"

 A scenario is investigated in which the leading-twist pion distribution
 amplitude phi_pi (x) is approximated by the pion decay constant f_pi
 for all essential values of the light-cone fraction x.

 A model for the light-front wave function Psi(x,k_perp) is proposed that
 produces such a distribution amplitude and has a rapidly decreasing
 (exponential for definiteness) dependence on the light-front energy
 combination k_perp2/x(1-x).

 It is shown that this model easily reproduces the fit of recent
 large-Q2 BaBar data on the photon-pion transition form factor. Some
 aspects of scenario with flat pion distribution amplitude are discussed.

 Talk is based on arXiv:0906.0323 [hep-ph]