Phenomenology of diphoton photoproduction at next-to-leading order

TL;DR

This paper develops a theoretical framework for diphoton photoproduction at NLO, compares predictions with experimental conditions, and explores its potential for probing generalized parton distributions, revealing significant NLO effects.

Contribution

It introduces a NLO QCD analysis of diphoton photoproduction in a collinear factorization framework, highlighting its sensitivity to GPD models and potential for GPD extraction.

Findings

NLO corrections are large and negative.

Predictions align with JLab experimental conditions.

Reaction is promising for GPD extraction.

Abstract

We develop the analysis of diphoton exclusive photoproduction in the kinematics where a collinear QCD factorization framework applies, namely nearly forward large invariant mass diphoton production. We work at the leading twist level and at the next-to-leading order (NLO) in the strong coupling constant $\alpha_S$. We compare our predictions for cross-sections with Born order calculations for the experimental conditions accessible to JLab experiments and show the interesting sensitivity of our results to various models of generalized parton distributions (GPDs). The NLO corrections are rather large and negative but do not prevent the studied reaction from being a promising tool for the extraction of C-dd GPDs, which do not contribute to either spacelike or timelike deeply virtual Compton scattering amplitudes.