Two-loop coefficient functions in deeply virtual Compton scattering: flavor-singlet axial-vector and transversity case

TL;DR

This paper computes two-loop coefficient functions for deeply virtual Compton scattering in QCD, focusing on flavor-singlet axial-vector and transversity cases, crucial for high-precision EIC data analysis.

Contribution

It completes the full NNLO calculation of coefficient functions in DVCS, revealing properties of transversity functions and their significance for experimental data.

Findings

Two-loop corrections are comparable to vector counterparts at moderate skewness.

Results reveal interesting transcendentality properties of transversity functions.

Numerical importance for upcoming Electron-Ion Collider measurements.

Abstract

We calculate the two-loop flavor-singlet axial-vector and gluon transversity coefficient functions for deeply virtual Compton scattering in QCD. We observe interesting properties regarding the transcendentality of the transversity coefficient function. Our results complete the calculation of the full next-to-next-to-leading order coefficient function in deeply virtual Compton scattering. Numerically, the two-loop corrections in the axial-vector and transversity channel are comparable to their vector counterpart at moderate skewness parameter {\xi} and hence indispensable for analyzing the upcoming high-precision data from the Electron-Ion Collider.