Deeply Virtual Compton Scattering at Next-to-Next-to-Leading Order

Area of Science:

• Particle physics
• Quantum chromodynamics
• High-energy physics

Background:

• Deeply virtual Compton scattering (DVCS) probes generalized parton distributions (GPDs).
• GPDs encode crucial information about the transverse and longitudinal momentum of quarks and gluons within protons.
• Anticipation of high-precision experimental data from the Electron-Ion Collider (EIC) necessitates precise theoretical predictions.

Purpose of the Study:

• To calculate the two-loop, next-to-next-to-leading order (NNLO) coefficient functions for DVCS.
• To analyze these calculations for the dominant Compton form factors H and E at high energies.
• To provide theoretical support for upcoming EIC experiments.

Main Methods:

• Performed two-loop calculations for DVCS coefficient functions.
• Focused on the NNLO corrections to the dominant Compton form factors H and E.
• Analyzed results at large energies and a specific input scale (Q^2 = 4 GeV^2).

Main Results:

• Calculated NNLO coefficient functions for DVCS, relevant for Compton form factors H and E.
• Observed a significant NNLO correction to the imaginary part of H, potentially a factor of 2.
• This large correction arises from cancellations between quark and gluon contributions in simple GPD models.

Conclusions:

• The NNLO corrections to DVCS are substantial and must be considered for accurate interpretation of EIC data.
• The calculated coefficient functions provide essential theoretical input for understanding proton structure.
• Future studies will benefit from these precise calculations in the context of GPDs.