Fany Zhao Memorial Lecture
July 17, 11 am, Large Seminar Room, BNL Physics Department
Speaker: Dr. Zhite Yu (Jefferson Lab)
Title: QCD Factorization of Hard Exclusive Processes and Tomographic Imaging of the Proton
Abstract: QCD factorization is essential for understanding hard scattering processes involving identified hadrons, as it systematically separates 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 present an overview of QCD factorization in hard exclusive processes, which give rise to two key types of parton correlation functions: distribution amplitudes (DAs) and generalized parton distributions (GPDs). GPDs offer a three-dimensional image of the proton in terms of parton longitudinal momentum fraction ($x$) and transverse spatial density. Unlike parton distribution functions (PDFs) in inclusive processes, GPDs and DAs are particularly challenging to access experimentally. I will address two major challenges in this context: (1) The separation of different types of GPDs that contribute simultaneously to a single cross section, for which I will introduce a novel framework that facilitates azimuthal modulation analysis; (2) The extraction of the $x$-dependence of GPDs, where I will highlight two processes that provide enhanced sensitivity and control.
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