New framework for extracting GPDs from exclusive photon electroproduction

Recently, a new framework for studying generic $2\to 3$ hard exclusive reactions, referred to as single-diffractive hard exclusive processes, has been introduced to provide a cleaner separation of the underlying physical mechanisms. In this work, we expand this formalism to the case of exclusive real-photon electroproduction off a nucleon, $e(\mathrm{\ell })+N(p)\to e({\mathrm{\ell }}^{\mathrm{\prime }})+N(p^{\mathrm{\prime }})+\gamma (q^{\mathrm{\prime }})$, which represents the classical channel for accessing generalized parton distributions (GPDs) in nucleons and nuclei. This extension enables a more systematic and physically transparent formulation of the reaction dynamics, paving the way for improved extractions of GPDs from experimental data as compared to existing approaches.