Deeply Virtual Compton Scattering (DVCS) on a Longitudinally Polarized Proton Target Using CLAS

DVCS has been identified as the cleanest process to access the Generalized Parton Distributions (GPDs) at medium energies through the so-called handbag mechanism. In electron scattering, scaling of the cross section has been measured at Jefferson Lab at photon a virtuality Q$^{2}$=2 GeV$^{2}$ [1], and DVCS has been measured in a large kinematic range using a polarized electron beam with CLAS [2]. This allowed access to a combination of GPD \textbf{\textit{H}} an \textbf{\textit{H}}-tilde with \textbf{\textit{H}} giving the dominant contribution. Using a longitudinally (along the beam line) polarized proton target the target asymmetry is dominantly described by the same two GPDs, but with \textbf{\textit{H}}-tilde giving the dominant contribution [3]. The combination of the two measurements will allow a precise separation of the two GPDs. The experiment (eg1-dvcs) ran during 3 periods in 2009 and collected high statistics data with the CLAS detector in Hall B. The quality of the data, and the status of the analysis will be described. The relevance of this data set and its kinematic extension to larger Q$^{2}$ with CLAS12 after the JLab energy upgrade will be discussed as well. [1] C. Munoz-Camacho, Phys. Rev. Lett.97, 262002, 2006. [2] F.X. Girod et al., Phys.Rev.Lett.100:162002, 2008. [3] S. Chen et al., Phys. Rev. Lett.97:072002, 2006.