[en] Reactions that proceed via a ΔT=0 transition are dominated by the longitudinal part of the current operator, whereas reactions that proceed via a ΔT=1 transition are purely the transverse. Therefore, in this thesis not only the dependence on the missing momentum p_m and on the transferred momentum q of the ³He(e, e' d)p, ⁴He(e, e' d)²H and ⁴He(e, e' d)pn reactions have been studied, but also the longitudinal, transverse and longitudinal-transverse interference structure functions have been separated. This was done in two different kinematical conditions, namely in parallel-kinematics, where the outgoing deuteron moves in the direction of the transferred momentum q, and in (q, ω)-constant kinematics, in which the momentum and energy transfer are held constant. Cross sections within a p_m range between 0 and 220 MeV/c have been measured at transferred momenta q of about 410, 500 and 600 MeV/c. All results are compared with available theoretical calculations. (orig./WL)

[en] A detector is described that is designed for the detection of light particles originating from heavy-ion collisions. The detector will be installed in the Huygens Vessel, a 4 π scattering facility for heavy-ion experiments. It consists of a matrix of 64 CsI(Tl) scintillation crystals measuring 48x48x10 mm³ each coupled with a light guide to a 10x10 mm² silicon photodiode. Several features of the system are described; the energy resolution was tested for gamma-rays, alpha-particles and ¹²C ions. (orig.)

[en] The (e,e'p) reaction on ⁴He nuclei was studied in kinematics designed to emphasize effects of nuclear short-range correlations. The measured cross sections display a peak in the kinematical regions where two-nucleon processes are expected to dominate. Theoretical models incorporating short-range correlation effects agree reasonably with the data

[en] Three structure functions have been determined in the reaction ¹⁶O(e,e'p)¹⁵N at Q²=0.20 (GeV/c)² for 1p_1/2 and 1p_3/2 knockout and for the excitation of the (5/2⁺,1/2⁺) doublet at E_x=5.3 MeV in ¹⁵N. The longitudinal-transverse interference structure function W_LT is enhanced by a factor 2.05±0.06±0.12 for 1p_3/2 knockout and by a factor 1.50±0.10±0.08 for 1p_1/2 knockout with respect to a calculation that gives a proper account of data taken in parallel kinematics. The longitudinal structure function W_L is also enhanced, albeit less with respect to these calculations

[en] The cross section for the ³He(e,e'd)p reaction has been measured as a function of the missing momentum p_m in (q,ω)-constant kinematics at beam energies of 370 and 576 MeV for values of the three-momentum transfer q of 412, 504 and 604 MeV/c. The L(+ TT), T and LT structure functions have been separated for q=412 and 504 MeV/c. The data are compared to three-body Faddeev calculations, including meson-exchange currents (MEC), and to calculations based on a covariant diagrammatic expansion. The influence of final-state interactions and meson-exchange currents is discussed. The p_m-dependence of the data is reasonably well described by all calculations. However, the most advanced Faddeev calculations, which employ the AV18 nucleon-nucleon interaction and include MEC, overestimate the measured cross sections, especially the longitudinal part, and at the larger values of q. The diagrammatic approach gives a fair description of the cross section, but under(over)estimates the longitudinal (transverse) structure function

[en] The (e,e''p) reaction on ⁴He nuclei was studied in kinematics designed to emphasize effects of nuclear short-range correlations. The measured cross sections display a peak in the kinematical regions where two-nucleon processes are expected to dominate. Theoretical models incorporating short-range correlation effects agree reasonably with the data. (orig.)

[en] The double-differential coincidence cross section for the reaction ¹H(e,e'p)π⁰ has been measured at Q²=0.1(GeV/c)² in a range in the invariant mass of 2--14 MeV above threshold. From the angular dependence of the data values of the pion s-wave multipoles E₀₊ and L₀₊ have been extracted. The results are compared to predictions from chiral perturbation theory and models based on an effective Lagrangian. None of the models is able to describe both the E₀₊ and the L₀₊ multipoles

No abstract available

[en] High-momentum components of proton momentum distributions in ²⁰⁸Pb have been studied from 300 to 500 MeV/c with the (e, e' p) reaction. Cross sections were measured with 180 keV excitation-energy resolution for transitions to the low-lying 1/2⁺,3/2⁺,11/2^-,5/2⁺, and 7/2⁺ states in ²⁰⁷Tl. The data are compared to distorted-wave impulse-approximation calculations with mean-field wave functions and with wave functions that include nucleon-nucleon correlations. The data are substantially larger than mean-field predictions. The observed excess strength at low excitation energy appears to be mainly due to long-range correlations and not to short-range and tensor correlations