Deeply virtual Compton scattering on neon

The measurement of Deeply Virtual Compton Scattering (DVCS) provides access to the spin structure of nucleons. Its description within the theoretical framework of generalized parton distributions offers a possibility to determine the total angular momentum carried by the quarks in the nucleon. In this thesis a cross section asymmetry with respect to the beam-helicity has been measured for hard exclusive electroproduction of photons from a neon target. The resulting asymmetry appears in the distribution of the produced photon in the azimuthal angle φ around the virtual-photon direction. Attributed to the interference between the Bethe-Heitler process and the DVCS process, the asymmetry gives access to the latter at the amplitude level. The DVCS reaction on nuclei proceeds through two different processes the coherent process that involves the nucleus as a whole and the incoherent process as the reaction on a single nucleon. The beam-helicity asymmetry and its dependences are studied for the coherent and incoherent sample, separately. The data presented has been accumulated by the HERMES experiment at DESY, scattering the HERA 27.6 GeV polarized positron beam off an unpolarized neon target. (orig.)