Reexamination of the astrophysical S factor for the alpha plus d -> Li-6+gamma reactionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 31 октября 2012 г.
Аннотация:Recently, a new measurement of the Li-6 (150 A MeV) dissociation in the field of Pb-208 has been reported [Hammache et al., Phys. Rev. C 82, 065803 (2010)] to study the radiative capture alpha + d -> Li-6 +gamma process. However, the dominance of the nuclear breakup over the Coulomb one prevented the information about the alpha + d -> Li-6 +gamma process from being obtained from the breakup data. The astrophysical S-24(E) factor has been calculated within the alpha - d two-body potential model with potentials determined from the fits to the alpha - d elastic scattering phase shifts. However, the scattering phase shift, according to the theorem of the inverse scattering problem, does not provide a unique alpha - d bound-state potential, which is the most crucial input when calculating the S-24(E) astrophysical factor at astrophysical energies. In this work, we emphasize the important role of the asymptotic normalization coefficient (ANC) for Li-6 +gamma -> alpha + d , which controls the overall normalization of the peripheral alpha + d -> Li-6 +gamma process and is determined by the adopted alpha - d bound-state potential. Since the potential determined from the elastic scattering data fit is not unique, the same is true for the ANC generated by the adopted potential. However, a unique ANC can be found directly from the elastic scattering phase shift, without invoking intermediate potential, by extrapolation the scattering phase shift to the bound-state pole [Blokhintsev et al., Phys. Rev. C 48, 2390 (1993)]. We demonstrate that the ANC previously determined from the alpha - d elastic scattering s-wave phase shift [Blokhintsev et al., Phys. Rev. C 48, 2390 (1993)], confirmed by ab initio calculations, gives S-24(E), which at low energies is about 38% less than the other one reported [Hammache et al., Phys. Rev. C 82, 065803 (2010)]. We recalculate also the reaction rates, which are lower than those obtained in that same study [Hammache et al., Phys. Rev. C 82, 065803 (2010)].