Asymptotic normalization coefficients, spectroscopic factors, and direct radiative capture rates

We compare the use of asymptotic normalization coefficients ~ANC’s! and spectroscopic factors determined from peripheral transfer reactions for determining the overall normalization of peripheral direct radiative capture reaction processes. We demonstrate that ANC’s provide a natural way to parametrize the rates of both peripheral transfer and direct capture reactions. Furthermore, ANC’s inferred from one reaction may be used in the analysis of a second reaction without further knowledge regarding their origin, and independent measurements of a given ANC may be combined to give an overall ‘‘best value’’ in a straightforward manner. In contrast, a spectroscopic factor derived from analysis of a peripheral transfer reaction can only be used in subsequent calculations if one has detailed knowledge of the single-particle bound state orbital that was assumed when the spectroscopic factor was obtained.