Photon structure studied at an electron ion collider

Abstract

A future electron ion collider (EIC) will be able to provide collisions of polarized electrons with protons and heavy ions over a wide range of center-of-mass energies (20 GeV to 140 GeV) at an instantaneous luminosity of $1{0}^{33}\ensuremath{-}{10}^{34}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$. One of its promising physics programs is the study of the partonic structure of quasireal photons. Measuring dijets in quasireal photoproduction events, one can effectively access the underlying parton dynamics of the photons. In this paper, we discuss the feasibility of tagging resolved photon processes and measuring the dijet cross section as a function of jet transverse momentum in the range of $0.01<{x}_{\ensuremath{\gamma}}^{\mathrm{rec}}<1$ at an EIC. It will be shown that both unpolarized and polarized parton distributions in the photon can be extracted, and that the flavor of the parton can be tagged at an EIC.