gamma)N-12 from the N-12 -> C-11+p asymptotic normalization coefficient Determination of the astrophysical S factor for C-11(p - Texas A&M University (TAMU) Scholar

Determination of the astrophysical S factor for C-11(p,gamma)N-12 from the N-12 -> C-11+p asymptotic normalization coefficient
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The evolution of very low-metallicity, massive stars depends critically on the amount of CNO nuclei that they produce. Alternative paths from the slow [Formula Presented] process to produce CNO seed nuclei could change their fate. The [Formula Presented] reaction is an important branch point in one such alternative path. At energies appropriate to stellar evolution of very low-metallicity, massive stars, nonresonant capture dominates the reaction rate. We have determined the astrophysical S factor for [Formula Presented] reaction using the asymptotic normalization coefficient for [Formula Presented] to fix the nonresonant capture rate. In our experiment, a 110 MeV [Formula Presented] radioactive beam was used to study [Formula Presented] peripheral transfer reaction and the asymptotic normalization coefficient, [Formula Presented] was extracted from the measured cross section. The contributions from the second resonance and interference effects were estimated using an R-matrix approach with the measured asymptotic normalization coefficient and the latest value for [Formula Presented] We find the S factor for [Formula Presented] is significantly larger than previous estimates. As a result, the required density for it to contribute is reduced, and more CNO material may be produced. 2003 The American Physical Society.