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The electrofission cross section of $^{182}\mathrm{W}$ was measured in the range 80--180 MeV. A pronounced inflexion, corresponding to a sharp structure in the (\ensuremath{\gamma},f) curve, shows up around 140 MeV. A photofission model, based on a photopion-deuteron reabsorption process, was worked out to explain this finding. Good agreement between calculation and experimental data was achieved.

We report precision {sup 1}H(e, e{sup '{pi}+})n measurements in the {Delta}(1232) resonance at Q{sup 2}=0.127(GeV/c){sup 2} obtained at the MIT-Bates out-of-plane scattering facility. These are the lowest, but nonzero, Q{sup 2} measurements in the {pi}{sup +} channel. The data offer tests of the theoretical calculations, particularly of the background amplitude contributions. The chiral effective field theory and Sato-Lee model calculations are not in agreement with this experiment.

The absolute electrofission cross sections of Au and Ta were measured in the range 25--180 MeV. The deduced photofission cross section shows, for both Au and Ta, a pronounced dip around the photopion threshold ([similar to]140 MeV). This ([gamma],[ital f]) dip is interpreted as a consequence of a probable photopion absorption in a stopped pion regime.''

The photoproduction process of neutral kaons on a liquid deuterium target is investigated near the threshold region, ${E}_{\ensuremath{\gamma}}=0.8\text{\ensuremath{-}}1.1$ GeV. ${K}^{0}$ events are reconstructed from positive and negative pions, and differential cross sections are derived. Experimental momentum spectra are compared with those calculated in the spectator model using a realistic deuteron wave function. Elementary amplitudes as given by recent isobar models and a simple phenomenological model are used to study the effect of the new data on the angular behavior of the elementary cross section. The data favor a backward-peaked angular distribution of the elementary $n(\ensuremath{\gamma},{K}^{0})\ensuremath{\Lambda}$ process, which provides additional constraints on current models of kaon photoproduction. The present study demonstrates that the $n(\ensuremath{\gamma},{K}^{0})\ensuremath{\Lambda}$ reaction can provide key information on the mechanism of the photoproduction of strangeness.

The absolute electrofission cross section of {sup 208}Pb was measured in the energy range 35--250 MeV, and the photofission cross section was deduced by means of the virtual-photon technique. A structure observed in the ({gamma},{ital f}) curve, around 200 MeV, was interpreted on the basis of recent calculations for the thermalization process which were performed in the framework of the intranuclear cascade model.

Cross sections were measured for the near-threshold electrodisintegration of ${}^{3}\mathrm{He}$ at momentum transfer values of $q=2.4,$ $4.4,$ and $4.7{\mathrm{fm}}^{\ensuremath{-}1}.$ From these and prior measurements the transverse and longitudinal response functions ${R}_{T}$ and ${R}_{L}$ were deduced. Comparisons are made against previously published and new nonrelativistic $A=3$ calculations using the best available nucleon-nucleon NN potentials. In general, for $ql2{\mathrm{fm}}^{\ensuremath{-}1}$ these calculations accurately predict the threshold electrodisintegration of ${}^{3}\mathrm{He}.$ Agreement at increasing q demands consideration of two-body terms, but discrepancies still appear at the highest momentum transfers probed, perhaps due to the neglect of relativistic dynamics, or to the underestimation of high-momentum wave-function components.

The (e,..cap alpha..) cross section in /sup 90/Zr has been measured at incident electron energies from 13.5 MeV to 66.5 MeV for ..cap alpha.. particles between 6.9 and 16.8 MeV. The (..gamma..,..cap alpha..) cross section was deduced from it assuming both E1 interaction and E2 interaction. The angular distribution of the (..gamma..,..cap alpha../sub 0/) cross section and an experiment using the bremsstrahlung plus electron beam make it clear that the E1 interaction is dominant over all the present energy range. The (..gamma..,..cap alpha..) cross section extracted by using E1 virtual photon spectra has a large bump above the excitation energy of 30 MeV in addition to a bump in the giant dipole resonance region. The (..gamma..,..cap alpha../sub 0/) cross section also has a bump at the giant dipole resonance which exhausts most of the (..gamma..,..cap alpha..) cross section in that region. The compound nucleus model was used successfully to explain the bump at the giant dipole resonance. The cross section above 30 MeV is discussed in terms of the pre-equilibrium ..cap alpha.. emission process combined with the quasi-deuteron model.