Hindrance of ^{16}O+^{208}Pb fusion at extreme sub-barrier energies

We analyze the fusion data for $^{16}$O+$^{208}$Pb using coupled-channels calculations. We include couplings to the low-lying surface excitations of the projectile and target and study the effect of the ($^{16}$O,$^{17}$O) one-neutron pickup. The hindrance of the fusion data that is observed at energies far below the Coulomb barrier cannot be explained by a conventional ion-ion potential and defining the fusion in terms of ingoing-wave boundary conditions (IWBC). We show that the hindrance can be explained fairly well by applying the M3Y double-folding potential which has been corrected with a calibrated, repulsive term that simulates the effect of nuclear incompressibility. We show that the coupling to one-neutron transfer channels plays a crucial role in improving the fit to the data. The best fit is achieved by increasing the transfer strength by 25% relative to the strength that is required to reproduce the one-neutron transfer data. The larger strength is not unrealistic because the calculated inelastic plus transfer cross section is in good agreement with the measured quasielastic cross section. We finally discuss the problem of reproducing the fusion data at energies far above the Coulomb barrier. Here we do not account for the data when we apply the IWBC but the discrepancy is essentially eliminated by applying the M3Y+repulsion potential and a weak, short-ranged imaginary potential.Comment: text and 8 fifure

Electron scattering from complex nuclei

Electron Scattering from Complex Nuclei, Part A covers the historical phases of experimental development in elastic and inelastic electron scattering. This five-chapter text presents the logical development of the underlying theory of electron scattering. After briefly discussing the history of electron scattering from nuclei, this book goes on describing the theory of elastic scattering from a point nucleus, both with Born approximation and the accurate solution of the Dirac equation, as well as the corresponding experiments. The following chapter considers the analysis of nuclear charge dis

Scattering by an elastic sphere embedded in an elastic isotropic medium

International audienceThe scattering of acoustic waves by an elastic sphere embedded in an elastic isotropic medium is investigated. Expressions for the scattered waves are given in terms of monostatic and bistatic scattering cross sections. The resonances of the solid sphere were determined numerically in the individual normal mode amplitudes; dispersion curves for the phase velocities of the circumferential waves were also obtained. Computations and experimental results for an aluminum sphere embedded in Plexiglas were in good agreement