The Coulomb interaction between the two protons is included in the calculation of proton-deuteron elastic scattering, radiative proton-deuteron capture and two-body electromagnetic disintegration of 3 He. The hadron dynamics is based on the purely nucleonic charge-dependent (CD) Bonn potential and its realistic extension CD Bonn + ∆ to a coupled-channel two-baryon potential, allowing for single virtual ∆-isobar excitation. Calculations are done using integral equations in momentum space. The screening and renormalization approach is employed for including the Coulomb interaction. Convergence of the procedure is found already at moderate screening radii. The reliability of the method is demonstrated. The Coulomb effect on observables is seen at low energies for the whole kinematic regime. In proton-deuteron elastic scattering at higher energies the Coulomb effect is confined to forward scattering angles; the ∆-isobar effect found previously remains unchanged by Coulomb. In electromagnetic reactions Coulomb competes with other effects in a complicated way.

A three-dimensional reduction of the two-particle Bethe-Salpeter equation is proposed. The proposed reduction is in the framework of light-front dynamics.It yields auxiliary quantities for the transition matrix and the bound state.

Spin-dependent inelastic electron scattering from polarized He is studied. The theoretical description uses the plane-wave impulse approximation. A spin-dependent spectral function, which summarizes all of the nuclear structure information on the process, is introduced. The formalism is developed for inclusive processes in all kinematic regimes of inelastic electron scattering. A comparison between theoretical predictions and experimental data is carried out in the region of quasifree scattering. The use of a polarized 'He target as a neutron spin target is discussed.

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The electromagnetic current of bound systems in the light-front is constructed in the Breit-Frame, in the limit of momentum transfer q + = (q 0 + q 3 ) vanishing. In this limit, the pair creation term survives and it is responsible for the covariance of the current. The pair creation term is computed for the j + current of a spin one composite particle in the Breit-frame. The rotational symmetry of j + is violated if the pair term is not considered.