Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 9Be+28Si, 144Sm, and 208Pb Systems at Near-Coulomb-Barrier Energies using Double Folding Potential

Based on the extended optical model with the double folding potential, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous $chi^{2}$ analyses are performed of elastic scattering and fusion cross section data for the $^{9}$Be+$^{28}$Si, $^{144}$Sm, and $^{208}$Pb systems at near-Coulomb-barrier energies. We find that the real part of the resultant DR part of the polarization potential is systematically repulsive for all the targets considered, which is consistent with the results deduced from the Continuum Discretized Coupled Channel (CDCC) calculations taking into account the polarization effects due to breakup. Further, it is found that both DR and fusion parts of the extracted polarization potentials satisfy the dispersion relation.

Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 7Li+208Pb System at Near-Coulomb-Barrier Energies using the Folding Potential

Simultaneous $chi^{2}$ analyses previously made for elastic scattering and fusion cross section data for the $^{6}$Li+$^{208}$Pb system is extended to the $^{7}$Li+$^{208}$Pb system at near-Coulomb-barrier energies based on the extended optical model approach, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and that both the DR and fusion parts of the polarization potential determined from the $chi^{2}$ analyses satisfy separately the dispersion relation. Further, we find that the real part of the fusion portion of the polarization potential is attractive while that of the DR part is repulsive except at energies far below the Coulomb barrier energy. A comparison is made of the present results with those obtained from the Continuum Discretized Coupled Channel (CDCC) calculations and a previous study based on the conventional optical model with a double folding potential. We also compare the present results for the $^7$Li+$^{208}$Pb system with the analysis previously made for the $^{6}$Li+$^{208}$Pb system.