Effect of E 1 excitations to the continuum: He 6 and <mml:…
2003; American Institute of Physics; Volume: 68; Issue: 5 Linguagem: Inglês
10.1103/physrevc.68.054601
ISSN1538-4497
AutoresN. Keeley, J. M. Cook, K. W. Kemper, B. T. Roeder, W. Weintraub, François Maréchal, К. Rusek,
Tópico(s)Advanced NMR Techniques and Applications
ResumoWe compare existing elastic scattering data for $^{6}\mathrm{He}+^{209}\mathrm{Bi}$ with new $^{6}\mathrm{Li}+^{209}\mathrm{Bi}$ data at the same center of mass energies relative to their respective Coulomb barriers. Total reaction cross sections obtained from optical model fits to the $^{6}\mathrm{Li}+^{209}\mathrm{Bi}$ elastic scattering data confirm previous suggestions that the total reaction cross section for $^{6}\mathrm{He}+^{209}\mathrm{Bi}$ is much larger than that for the $^{6}\mathrm{Li}+^{209}\mathrm{Bi}$ system at similar energies relative to the Coulomb barrier. Continuum-discretized coupled channels calculations suggest that the enhanced reaction cross section for $^{6}\mathrm{He}$ is due to the large $E1$ excitation strength to the continuum, absent in $^{6}\mathrm{Li}$. However, this conclusion is still tentative, as the calculations predict a large peak in the total $\ensuremath{\alpha}$ yield at forward angles which the currently available data are unable to confirm, due to their not extending to sufficiently small angles. New precise data for the elastic scattering and total $\ensuremath{\alpha}$ yield at forward angles for the $^{6}\mathrm{He}+^{209}\mathrm{Bi}$ system are required to confirm the contribution of $E1$ excitation to the continuum to the total reaction cross section.
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