Uncertainties in extracting S-17 from transfer reactions

The transfer reaction Be-7(d,n)B-8 is modeled for the recent low experiment al energies using the distorted-wave Born approximation (DWBA). Tests of th e validity of the asymptotic normalization constant method for the extracti on of the S-17 astrophysical factor are performed. We show that a periphera l assumption is no longer accurate for center-of-mass energies greater than approximately 15 MeV. In all cases we found that core deformation and/or e xcitation effects to be small as long as the optical potential for the entr ance channel is not strongly surface peaked. Multistep corrections to the D WBA were found to be small. We also emphasize that the lack of knowledge of the optical potentials for the entrance and outgoing channels induces seve re uncertainties in the extracted S-17 astrophysical factor. [S0556-2813(99 )04704-4].