<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Theory Center Seminar<br><div>Monday, March 5<br>1:00pm<br>CEBAF Center, Room L102<br><font color="#0f61c8"><b><br></b></font><b><span style="font-size: 13px;">Andreas Metz (Temple U.)</span></b><br><font size="2"><b>Twist-3 GPDs in Deeply-Virtual Compton Scattering</b></font><br><font size="2">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.</font><br><font color="#0f61c8"><br></font>The bluejeans link for the remote connection is<br><a href="https://bluejeans.com/335716039">https://bluejeans.com/335716039</a><br><font color="#0f61c8"><br></font><br></div><br></body></html>