[Jlab-seminars] Theory Center Seminar

[Mary Fox]

Theory Center Seminar
Monday, June 11, 2018
1:00 p.m. (coffee at 12:45 p.m.)
CEBAF Center, Room L102

Peter Kroll
Wuppertal University

*Wide-Angle Photoproduction of Pions*

After an introduction in the handbag approach to hard wide-angle 
processes such as real Compton scattering or photoproduction of pions, 
it is reported on a calculation of the latter process to twist-3 
accuracy. In contrast to earlier work both the 2-particle as well as the 
3-particle twist-3 contributions are taken into account. It is shown 
that both the contributions are needed for a consistent result that 
respects gauge invariance and crossing properties. The use of the 
twist-3 pion distribution amplitudes go along with form factors that 
represent 1/x-moments of transversity generalized distribution 
amplitudes. The numerical studies reveal the dominance of the twist-3 
contribution. With it fair agreement with the recent CLAS measurement of 
the pi^0 cross section is achieved. Spin-dependent observables are also 
discussed.


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