Are coupled channel effects important for the asymptotic normalization coefficient method?
Abstract
DWBA calculations are commonly used in the analysis of peripheral transfer reactions, to extract the asymptotic normalization coefficient (ANC). This quantity is uniquely related to the zero energy S-factor useful for astrophysical purposes. The aim of this work is to test the adequacy of the DWBA formalism. For a set of transfer reactions from which ANCs have been extracted, we perform full coupled channels calculations. We include the most relevant inelastic channels for both the entrance and exit partitions. The results show that the reactions ${}^{13}\mathrm{C}{(}^{3}\mathrm{He}{,d)}^{14}{\mathrm{N}}_{\mathrm{g}.\mathrm{s}.}$ and ${}^{14}\mathrm{N}{(}^{7}\mathrm{Be}{,}^{8}\mathrm{B}{)}^{13}{\mathrm{C}}_{\mathrm{g}.\mathrm{s}.}$ are free from coupling effects, even if some of the excited final-state channels are not. For ${}^{10}\mathrm{B}{(}^{7}\mathrm{Be}{,}^{8}\mathrm{B}{)}^{9}{\mathrm{Be}}_{\mathrm{g}.\mathrm{s}.},$ the ANC should be extracted with caution. If the ${}^{10}\mathrm{B}$ and ${}^{9}\mathrm{Be}$ behave similarly in this reaction as in the ${}^{9}\mathrm{Be}{(}^{3}\mathrm{He}{,d)}^{10}\mathrm{B}$ case, couplings effects should not be neglected.