Abstract. We introduce generalized quark and gluon distributions in the deuteron, which can be measured in exclusive processes like deeply virtual Compton scattering and meson electroproduction. We discuss the basic properties of these distributions, and point out how they probe the interplay of nucleon and parton degrees of freedom in the deuteron wave function.Introduction. The partonic structure of the deuteron has been explored in terms of the parton distributions accessible in deep inelastic scattering [1], and in terms of the form factors measured in elastic lepton-deuteron processes [2,3]. It is natural to ask what can be learned from generalized parton distributions (GPDs), introduced not long ago in [4,5]. For the nucleon case it has been shown that these quantities contain unique information about the dynamics of quarks and gluons in QCD bound states, beyond what can be unraveled from ordinary parton distributions and form factors. Here we extend these studies to the case of the deuteron, with the aim of providing the theoretical framework to analyze and interpret present and future measurements with deuteron targets. We restrict ourselves to parton distributions of twist two, and to the parton helicity conserving sector, which is relevant in most phenomenological applications. Quark and gluon helicity flip GPDs can be treated with the same methods.

Abstract. We study deeply virtual Compton scattering and deep exclusive meson electroproduction on a deuteron target. We model the Generalized Quark Distributions in the deuteron by using the impulse approximation for the lowest Fock-space state on the light-cone. We study the properties of the resulting GPDs, and verify that sum rules violations are quite small in the impulse approximation. Numerical predictions are given for the unpolarized cross sections and polarization asymmetries for the kinematical regimes relevant for JLab experiments and for HERMES at HERA. We conclude that the signal of coherent scattering on the deuteron is comparable to the one on the proton at least for low momentum transfer, providing support to the feasibility of the experiments. The short distance structure of the deuteron may thus be scrutinized in the near future.