Studying photon structure at an EIC
  A future Electron-Ion Collider (EIC) will deliver luminosities of $10^{33} - 10^{34}$ cm$^{-2}$s$^{-1}$ for collisions of polarized electrons and protons and heavy ions over a wide range of center-of-mass energies (40 $\mathrm{GeV}$ to 145 $\mathrm{GeV}$). One of its promising physics programs is to study the partonic structure of quasi-real photons. Measuring di-jet in photoproduction events, one can effectively access the underlying parton dynamics of the photons through the selection of the resolved photon processes. In this paper, we discuss the feasibility of tagging resolved photon processes and measuring the di-jet cross section as a function of jet transverse momentum in ranges of $x_{\gamma}^{rec}$ at an EIC. These studies show that parton distributions in the photon can be extracted at an EIC. 
Xiaoxuan Chu, Elke-Caroline Aschenauer and Jeong-Hun Lee
nucl-ex hep-ph