No Arabic abstract
Herein, we investigated the channel coupling (CC) effect on the elastic scatterings of lithium (Li) isotopes ($A =$ 6--9) for the $^{12}$C and $^{28}$Si targets at $E/A =$ 50--60 MeV. The wave functions of the Li isotopes were obtained using the stochastic multi-configuration mixing (SMCM) method based on the microscopic-cluster model. The proton radii of the $^{7}$Li, $^{8}$Li, and $^{9}$Li nuclei became smaller as the number of valence neutrons increased. The valence neutrons in the $^{8}$Li and $^{9}$Li nuclei exhibited a glue-like behavior, thereby attracting the $alpha$ and $t$ clusters. Based on the transition densities derived from these microscopic wave functions, the elastic-scattering cross section was calculated using a microscopic coupled-channel (MCC) method with a complex $G$-matrix interaction. The existing experimental data for the elastic scatterings of the Li isotopes and $^{10}$Be nuclei were well reproduced. The Li isotope elastic cross sections were demonstrated for the $^{12}$C and $^{28}$Si targets at $E/A$ =53 MeV. The glue-like effect of the valence neutrons on the Li isotope was clearly demonstrated by the CC effect on elastic scattering. Finally, we realize that the valence neutrons stabilized the bindings of the core parts and the CC effect related to core excitation was indeed reduced.
The recent works by the present authors and their collaborator predicted that the real part of heavy-ion optical potentials changes its character from attraction to repulsion around the incident energy per nucleon $E =$ 200 -- 300 MeV/u on the basis of the complex $G$-matrix interaction and the double-folding model (DFM) and revealed that the three-body force plays an important role there. In the present paper, we have analyzed the energy dependence of the coupling effect with the Microscopic Coupled Channel (MCC) method and its relation to the elastic and inelastic-scattering angular distributions in detail in the case of the $^{12}$C + $^{12}$C system in the energy range of $E =$ 100 -- 400 MeV/u. The large channel coupling effect is clearly seen in the elastic cross section although the incident energies are enough high. The dynamical polarization potential is derived to investigate the channel coupling effect. Moreover, we analyze the effect of imaginary part of the coupling potential on elastic and inelastic cross sections.
While it is well established that the ground state reorientation coupling can have a significant influence on the elastic scattering of deformed nuclei, the effect of such couplings on transfer channels has been much less well investigated. In this letter we demonstrate that the 208Pb(7Li,6He)209Bi proton stripping reaction at an incident energy of 52 MeV can be well described by the inclusion of the 7Li ground state reorientation coupling within the coupled channels Born approximation formalism. Full finite-range distorted wave Born approximation calculations were previously found to be unable to describe these data. Addition of coupling to the 0.478-MeV 1/2- excited state of 7Li, together with the associated two-step transfer path, has little or no influence on the shape of the angular distributions (except that for stripping leading to the 1.61-MeV 13/2+ level of 209Bi which is significantly improved) but does affect appreciably the values of the 209Bi -> 208Pb + p spectroscopic factors. Implications for experiments with weakly-bound light radioactive beams are discussed.
We present theoretical predictions for electron scattering on the N = 14, 20, and 28 isotonic chains from proton-deficient to proton-rich nuclei. The calculations are performed within the framework of the distorted-wave Born approximation and the proton and neutron density distributions are evaluated adopting a Relativistic Hartree-Bogoliubov (RHB) approach with a density dependent meson-exchange interaction. We present results for the elastic and quasi-elastic cross sections and for the parity-violating asymmetry parameter. Owing to the correlations between the evolution of the electric charge form factors along each chain with the underlying proton shell structure of the isotones, elastic electron scattering experiments on isotones can provide useful informations about the occupation and filling of the single-particle levels of protons.
We investigate the sensitivity of the medium effect in the high-density region on the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. The medium effect including three-body-force (TBF) effect is investigated with two methods. In the both methods, the medium effect is clearly seen on the potential and the elastic cross section. Finally, we make clear the crucial role of the TBF effect up to $k_F =$ 1.6 fm$^{-1}$ in the nucleus-nucleus elastic scattering.
We investigate the property of the high-density nuclear matter probed by the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. The medium effect including three-body-force (TBF) effect is investigated with present two methods based on the frozen density approximation (FDA). The medium effect is clearly seen on the potential and the elastic cross section for the $^{16}$O + $^{16}$O system at $E/A =$ 70 MeV. The crucial role of the medium effect is also confirmed with other effective nucleon-nucleon ($NN$) interactions. In addition, the present methods are applied to other heavy-ion elastic scattering systems. Again, the medium effect is clearly seen in the heavy-ion elastic cross section. The medium effect on the elastic cross section becomes invisible with the increase of the target mass and the incident energy (up to $E/A =$ 200 MeV). However, the medium effect is again important to fix the heavy-ion scattering over $E/A =$ 200 MeV. Finally, we make clear the crucial role of the TBF effect up to $k_F =$ 1.6 fm$^{-1}$ in the nucleus-nucleus elastic scattering.