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The photoproduction of ρ0-mesons and Δ-baryons at photon energies up to 2.6 GeV has been studied with the SAPHIR detector at the electron stretcher ELSA. Total and differential cross-sections were obtained. The decay angular distributions of ρ0-mesons show that s-channel helicity conservation, which is valid at high photon energies, is broken near threshold. The energy dependencies of the decay angular distributions in the helicity system as well as in the Gottfried-Jackson system hint at small s- or u-channel resonance contributions. For the reactions γp → Δ{++}π- and γp → Δ0π+ new data on cross-sections are presented.

Isoscalar monopole and dipole transitions are investigated in the medium and heavier systems, such as $$^{44}\hbox {Ti}$$ and even $$^{104-110}\hbox {Te}$$ nuclei by employing the macroscopic $$\alpha $$ cluster model of $$\alpha + {}^{40}\hbox {Ca}$$ and $$\alpha + {}^{100-106}\hbox {Sn}$$ , respectively. Theoretical calculations predict that the strengths of the monopole and dipole transitions are strongly enhanced in the excitation energy below 10 MeV. These low-lying enhancements are induced by the excitation in the relative motion of the $$\alpha $$ cluster and the residual nucleus, and the magnitudes of the transition matrix element are comparable to the single nucleon excitation, which requires much higher excitation energy than the energy for the $$\alpha $$ excitation. The electric dipole strength is also calcluated for $$^{135}\hbox {Cs}$$ with the cluster model of $$\alpha + {}^{131}\hbox {I}$$ , which is a kind of nuclear waste. The application of the monopole and dipole transitions involving the $$\alpha $$ emission to the nuclear transmutation of the nuclear wastes is also discussed.

The emission probability of Intermediate Mass Fragments (IMFs) in non-central reactions has been investigated in collisions of heavy $$^{124}\hbox {Xe}$$ projectiles with the two different medium-mass targets of $$^{64}\hbox {Ni}$$ and $$^{64}\hbox {Zn}$$ at the laboratory energy of 35 A MeV. The two colliding systems differ only for the target atomic number Z and, consequently, for the isospin N/Z ratio. The probability of IMFs emission from the projectile-like fragment has been measured, showing an enhancement of the IMFs emission for the neutron rich $$^{64}\hbox {Ni}$$ target. Most of the observed projectile break-up yield is associated with the production of only one IMF, that is, a quasi-binary splitting of projectile in two fragments in a broad range of charge asymmetry. For the events with one IMF, the relative contributions of the dynamical and statistical emissions have been evaluated. We find an enhancement of dynamical break-up probability for the neutron rich target with respect to the neutron poor one. The analysis suggests influence of the target isospin in inducing the dynamical break-up of projectile-like fragments. The new data have been also compared with previous published results of $$^{112,124}\hbox {Sn}$$ + $$^{58,64}\hbox {Ni}$$ systems, in order to disentangle between isospin effects against system-size effects on the emission probability. The comparisons between previous and new data suggest that the dynamical break-up is determined by the N/Z content of both projectile and target; for the cases here investigated, the influence of the system size on the dynamical emission probability can be excluded.

The discovery more than twenty years ago, by the EMC Collaboration, that the deep-inelastic-scattering DIS structure functions are influenced by the nuclear environment stunned the nuclear physics community and brought quarks and gluons into the field with great impact. A great length of time has passed, but despite a semi-infinite number of papers on the subject, there is no explanation that is universally accepted. Many models (related in one way or another to QCD) have been successful in reproducing data for deep inelastic scattering on nuclear targets, but fewer have described both the DIS and nuclear Drell-Yan experiments. Although there are some positive indications, no model has been used to predict correctly and unambiguously new independent phenomena. We review the history and discuss the best experimental prospects for future discovery.