Speaker
Description
Photons can acquire a hadronic structure through quantum fluctuations, effectively becoming a superposition of the $U(1)$ gauge boson of QED and QCD quark-gluon configurations. Consequently, in electron-proton scattering, partons from both the resolved photon and proton can participate in strong interactions, revealing the resolved photon's hadronic structure. Although this nonperturbative structure remains poorly understood, it is critical for photoproduction of jets studies at the EIC, where the process is particularly sensitive to the gluon distribution of the proton. Additionally, QCD factorization is seen to be violated by a factor of $\sim 0.34$ when resolved photons contribute to the photoproduction of dijets alongside pointlike photons at HERA, raising a critical question of whether factorization is genuinely broken for resolved photons or whether the issue stems from the lack of precise knowledge of the resolved photon's hadronic structure. As a unique opportunity to unravel the largely uncharted hadronic structure of the photon, we present ongoing progress in the first lattice QCD program to compute the photon's $x$-dependent hadronic structure using the RBC/UKQCD domain wall fermion ensembles with lattice spacings of $0.06,~0.09$ and $0.12$ fm.