Complete Separation of Deeply Virtual Photon and π Electroproduction Observables of Unpolarized Protons

We propose to use the incident beam energy dependence of the Bethe-Heitler (BH) and deeply virtual Compton scattering (DVCS) amplitudes to isolate the BH·DVCS interference term from the pure DVCS 2 contribution to the photon electroproduction (ep → epγ) cross section in the deeply virtual regime. This is a necessary step in order to extract meaningful information about Generalized Parton Distributions (GPDs) through DVCS cross sections. The understanding of the pure DVCS contribution to the cross section is essential in order to plan future 12 GeV DVCS measurements, some of which were already approved by PAC30. In order to measure the size of the pure DVCS contribution to the electroproduction cross section, we request 400 h of beam time (plus 6 additional days for calorimeter calibration and optical curing), with a total of three different beam energies. This beam time will also allow the measurement of the 5 response functions of the exclusive deep virtual π 0 channel, in particular dσ L and dσ T by a conventional Rosenbluth separation. This separation, as a function of Q 2 , is essential for testing the factorization of dσ L in the deeply virtual ep → epπ 0 reaction.