[Jlab-seminars] Theory Center Seminar

[Mary Fox]

Theory Center Seminar
Monday, March 5, 2018
1:00 p.m. (coffee at 12:45 p.m.)
CEBAF Center, Room L102

Andreas Metz
Temple University

*Twist-3 GPDs in Deeply Virtual Compton Scattering

*The sub-leading power of the scattering amplitude for deeply-virtual 
Compton scattering (DVCS) off
the nucleon contains leading-twist and twist-3 generalized parton 
distributions (GPDs).  We point out
that in DVCS, at twist-3 accuracy, one cannot address any individual 
quark twist-3 GPD.  Accessible are
exclusively linear combinations involving both vector and axial-vector 
twist-3 GPDs.  This implies, in
particular, that in DVCS there is no direct access to the (kinetic) 
orbital angular momentum of quarks
through twist-3 GPDs.  Moreover, using the quark-target model, we find 
that twist-3 GPDs can be
discontinuous.  The discontinuities however vanish in the DVCS 
amplitude, which further supports the
hypothesis of factorization at twist-3 accuracy.


The bluejeans link for the remote connection is 
https://bluejeans.com/335716039

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