Final State Interactions and Relativistic Effects in Exclusive Electron Scattering from the Deuteron

For a quantitative description of exclusive electron scattering data at high energies, one has to take into account both relativistic effects and an appropriate description of final state interactions. In the rst part, we use a recent approach for the relativistic treatment of the electromagnetic current operator which does not involve an approximation in the transferred energy or transferred momentum, in contrast to the strict non-relativistic reduction which is frequently used. In the second part, we apply Glauber theory to the calculation of the final state interaction. The different effects of final state interactions on the S-wave and D-wave of the nuclear wave function are discussed, and their implications for the experimental discrimination between different theoretical models are explored. Currently, there are many exclusive electron scattering experiments being performed or in the planning stage at high energies, e.g. at Bates, TJNAF, NIKHEF and MAMI. A sketch of the reaction is provided in Fig. 1. Ideally, one would use a microscopic Hamiltonian for the description of both the nuclear bound state and the-in general rather complicated-hadronic final state. Such a microscopic Hamiltonian would also contain a minimal coupling for the photon, so that the initial state, the final state and the electromagnetic current operator would all be treated consistently in a microscopic, relativistic fashion. In practice, it is very difcult to perform a consistent calculation of both nuclear ground state and final hadronic scattering state, and especially for medium and heavy nuclei, it is unlikely that a consistent, fully microscopic and therefore relativistic treatment will be available in the near future. At present, there are several approximate calculations for particular elec-tronuclear reactions available for few-body systems 1;2;3. However, it is difcult to extend these approaches for the few-body systems to energies above the pion emission threshold. With the considerable effort one expects will be put into experimental studies in this eld, in the next few years calculations for the few GeV regime for reactions with deuteron targets will hopefully become available, although even this is not trivial. For heavy nuclei, there are only relativistic mean-eld calculations available. Therefore, at present in practice one splits up the problem into three sep