Seminarium "Teoria cząstek elementarnych i kosmologia"

Generalized parton distributions (GPDs) allow a detailed study of the internal structure of nuclei. In the appropriate kinematical limit, one can express an amplitude of a scattering process in terms of relevant GPDs convoluted with perturbatively computable quantities using so-called collinear factorization. The quest for extraction of GPDs from experimental data necessitates the study of different exclusive processes. In this talk, I will discuss the recent analysis of the photoproduction of a near-forward large mass diphoton at the leading twist in a proton+photon process at the next-to-leading order in strong coupling. I will describe the problem of soft and collinear divergences present in loop calculations, and how it is solved in the framework of collinear factorization. I will present the results of the one-loop pQCD calculation, and discuss the phenomenological analysis done using the PARTONS software framework.