Asymptotic normalization coefficients from direct transfer reactions and astrophysical S factors

Peripheral transfer reactions can be used to determine asymptotic normalization coefficients (ANC). These coefficients, which specify the normalization of the tail of the overlap function, determine S factors for direct capture reactions at astrophysical energies. A variety of proton transfer reactions involving both stable and radioactive beams have been used to measure ANC's. Tests have demonstrated that ANC's determined from proton transfer reactions can be used to calculate astrophysical direct capture rates to within 9%. The B-10(Be-7,B-8)Be-9 and N-14(Be-7,B-8)C-13 reactions have been used to measure the ANC appropriate for determining the Be-7(p,gamma)B-8 rate, and the N-14(C-11,N-12)C-13 reaction has been used to measure the ANC required to calculate the C-11(p,gamma)N-12 rate.