Speaker
Description
In electron-proton collisions, the incoming electron is coupled directly to a parton of the proton with the exchange of a virtual photon, which has properties close to a real photon when the transfer momentum is small. In QCD, the exchanged physical photon can be approximated as a superposition of the bare photon state (direct process) and the hadronic photon state (resolved process). We discuss how the measurement of di-jets can be utilized to separate these two types of processes. Measuring di-jets in quasi-real photoproduction events, one can effectively access the underlying parton structure of the exchanged photons.
The unpolarized photon PDFs can be extracted with high precision from the di-jet cross section. It will be shown that the polarized PDFs for photons can for the first time be extracted by measuring the double spin asymmetry as function of x_{\gamma}. A tagging method is used to probe the flavor of the parton content experimentally. In addition, we will discuss the effects of the underlying event on these measurements.
