One-Loop Corrections and All Order Factorization In Deeply Virtual Compton Scattering

TL;DR

Deeply virtual Compton scattering is analyzed to establish a robust factorization framework in perturbative QCD. The authors compute one-loop DVCS amplitudes for quark and gluon targets, identify infrared structures, and demonstrate that soft divergences cancel while collinear parts factorize into off-forward parton distributions, which evolve with off-forward kernels. They formulate a generalized operator product expansion including total derivative operators and derive the corresponding Wilson coefficients at next-to-leading order, ensuring consistency with the DIS limit. The work thus provides an all-orders factorization proof for DVCS and supplies the NLO ingredients needed to extract OFPDs from experimental data.

Abstract

We calculate the one-loop corrections to a general off-forward deeply-virtual Compton process at leading twist for both parton helicity-dependent and independent cases. We show that the infrared divergences can be factorized entirely into off-forward parton distributions, even when one of the two photons is onshell. We argue that this property persists to all orders in perturbation theory. We obtain the next-to-leading order Wilson coefficients for the general leading-twist expansion of the product of two electromagnetic currents in the \overline{\rm MS} scheme.

Figures (5)

• Figure 1: The handbag diagram for the general two photon process.
• Figure 2: Diagrams for Compton scattering on an onshell quark to order $\alpha_s$.
• Figure 3: The momentum flow in the box diagram
• Figure 4: Diagrams for gluon Compton scattering at one loop.
• Figure 5: General reduced diagrams for the DVCS process.