Sakurai Prize: QCD Factorization of Hard Exclusive Processes and Tomographic Image of Proton

QCD factorization is crucial for our understanding of hard scattering experiments involving identified hadrons, as it consistently factorizes nonperturbative hadronic dynamics into universal parton correlation functions, which in turn enable the study of the partonic structure of hadrons. In this talk, I will provide an overview of QCD factorization for hard exclusive processes, which result in two types of parton correlation functions: distribution amplitudes (DAs) and generalized parton distributions (GPDs). GPDs provide a three-dimensional image of the proton in terms of parton longitudinal momentum fraction ($x$) and transverse spatial densities. Unlike PDFs for inclusive processes, measuring GPDs (and DAs) is challenging, particularly concerning their $x$-dependence. After discussing the difficulties and challenges, I will highlight two processes that offer improved control over the extraction of $x$-dependence.