At sufficiently large proton energies, Glauber multiple-scattering theory offers good opportunities for describing the final state interactions in electro-induced proton emission off nuclear targets. A fully unfactorized relativistic formulation of Glauber multiple-scattering theory is presented. The effect of truncating the Glauber multiple-scattering series is discussed. Relativistic effects in the description of the final-state interactions are found not to exceed the few percent level. Also the frequently adopted approximation of replacing the wave functions for the individual scattering nucleons by some average density, is observed to have a minor impact on the results when obtained in the independent-particle model. Predictions for the separated 4 He(e, e p) response functions are given in quasi-elastic kinematics and a domain corresponding with 1 Q 2 2 (GeV) 2 .

A study of γp → KΣ processes in an isobar model at tree level is reported. By comparing model calculations to the published SAPHIR data, we explore the possible role of different isospin I = 1 2 (N * ) and I = 3 2 (∆ * ) resonances in the reaction dynamics. In our analysis, the inclusion of the "missing" D13(1895) resonance does only slightly improve the global description of the Σ photoproduction data. More convincing signals for the presence of such a "missing" resonance emerged in the analysis of the isospin related γp → K + Λ reaction. Various implementations of the nonresonant part of the Σ photoproduction amplitude are presented. The sensitivity of the computed observables and extracted resonance parameters to the uncertainties inherent to the treatment of the non-resonant (background) diagrams are discussed.

We discuss the role of hyperon resonances in the u-channel when modeling p γ, K + Λ processes in an effective Lagrangian approach. Without the introduction of hyperon resonances, one is forced to use soft hadronic form factors with a cutoff mass which is at best two times the kaon mass. After inclusion of the hyperon resonances in the u-channel, we obtain a fair description of the data with a cutoff mass of the order of 1.8 GeV.

The photoproduction p(␥,K ϩ )⌳ process is studied within a field-theoretic approach. It is shown that the background contributions constitute an important part of the reaction dynamics. We compare predictions obtained with three plausible techniques for dealing with these background contributions. It appears that the extracted resonance parameters drastically depend on the applied technique. We investigate the implications of the corrections to the functional form of the hadronic form factor in the contact term, recently suggested by Davidson and Workman ͓Phys. Rev. C 63, 025210 ͑2001͔͒. The role of background contributions and hadronic form factors for the identification of the quantum numbers of ''missing'' resonances is discussed.

The effect of tensor nucleon-nucleon correlations upon exclusive and semiexclusive electronuclear reactions is studied. Differential cross sections for the semiexclusive 16 O(e,eЈp) and exclusive 16 O(e,eЈpn) processes are computed by explicitly evaluating the dynamical electromagnetic coupling to a tensor correlated nucleon pair. In both reaction channels the tensor correlations contribute in a very substantial way. Tensor correlations are found to generate more electronuclear strength than central Jastrow correlations do.PACS number͑s͒: 25.30. Ϫc, 21.30.Fe, 24.10.Ϫi In the history of nuclear physics, it has been notoriously difficult to detect signals that directly point towards phenomena beyond the scope of the effective mean-field theories. This holds, in particular, for the short-range correlations that reflect the remnants of the hard-core part of the nucleonnucleon (NN) force in the medium. Recently, manifestations for strongly correlated proton pairs and the existence of Jastrow-like correlations emerged from the simultaneous detection of two protons upon absorption of one ͑virtual͒ photon by an atomic nucleus ͓1,2͔. Nuclear many-body theories have produced vastly different predictions for the short-range behavior of nuclei. The ongoing exclusive A(e,eЈpp) studies are expected to provide stringent tests of these theories. The correlations probed in proton-proton knockout are predominantly the state-independent scalar ones ͑often referred to as Jastrow correlations͒ related to the hard core part of the NN force. The tensor force, which is operative at intermediate internucleon distances (Ϸ1 -2.5 fm͒, is established to be an important ingredient of the NN force in the medium and is believed to be another source of important NN correlations which go beyond the mean-field level ͓3͔. High momentum components in the deuteron wave function, for example, are ascribed to a D-state admixture and are a direct manifestation of the presence of tensor correlations in the proton-neutron system. For a long time, the tensor interaction has been established to be a rather weak but essential ingredient of the effective NN force. Despite intensive research a recent review ͓4͔ quoted its role as ''elusive.'' Earlier studies of the role played by tensor correlations in electron scattering concentrated on inclusive A(e,eЈ) response functions, for which there are many competing effects and unambiguous information on the tensor correlations, might be difficult to extract ͓5,6͔. In the near future, exclusive experiments that aim at probing both the proton-proton and proton-neutron correlations will be performed at MAMI and TJNAF. At MAMI, where central short-range correlations in nuclei are being studied with the aid of the A(e,eЈpp) reaction ͓2,7͔, highresolution A(e,eЈpn) measurements have been scheduled for the target nuclei 3 He ͓8͔ and 16O ͓9͔. These measurements will be performed at four-momentum transfers of the order Q 2 Ϸ0.05 (GeV/c) 2 . At TJNAF, on the other hand, the small distance structure of nuclei will be probe...