Stellar reaction rate for Mg22+p→Al23 from the asymptotic normalization coefficient in the mirror nuclear system Ne22+n→Ne23
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The production of Na22 in ONe novae can be influenced by the Mg22(p,γ)Al23 reaction. To investigate this reaction rate at stellar energies, we have determined the asymptotic normalization coefficient (ANC) for Mg22+p→Al23 through measurements of the ANCs in the mirror nuclear system Ne22+n→Ne23. The peripheral neutron-transfer reactions C13(C12,C13)C12 and C13(Ne22,Ne23)C12 were studied. The identical entrance and exit channels of the first reaction make it possible to extract independently the ground-state ANC in C13. Our experiment gives Cp1/22(C13)=2.24±0.11 fm-1, which agrees with the value obtained from several previous measurements. The weighted average for all the obtained Cp1/22 is 2.31±0.08 fm-1. This value is adopted to be used in obtaining the ANCs in Ne23. The differential cross sections for the reaction C13(Ne22,Ne23)C12 leading to the Jπ=5/2+ and 1/2+ states in Ne23 have been measured at 12 MeV/u. Optical model parameters for use in the DWBA calculations were obtained from measurements of the elastic scatterings Ne22+C13 and Ne22+C12. The extracted ANC for the ground state in Ne23, Cd5/22=0.86±0.08±0.12 fm-1, is converted to its corresponding value in Al23 using mirror symmetry to give Cd5/22(Al23)=(4.63±0.77) ×103 fm-1. The astrophysical S factor S(0) for the Mg22(p,γ) reaction was determined to be 0.96±0.11 keV b. The consequences for nuclear astrophysics are discussed. © 2010 The American Physical Society.
author list (cited authors)
Al-Abdullah, T., Carstoiu, F., Chen, X., Clark, H. L., Fu, C., Gagliardi, C. A., ... Tribble, R. E.