New astrophysical S factor for the {sup 15}N(p,{gamma}){sup 16}O reaction via the asymptotic normalization coefficient (ANC) method
- Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)
- Nuclear Physics Institute, Czech Academy of Sciences, 250 68 Rez near Prague (Czech Republic)
- Universita di Catania and INFN Laboratori Nazionali del Sud, Catania (Italy)
The {sup 15}N(p,{gamma}){sup 16}O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong J{sup {pi}}=1{sup -} resonances at E{sub R}=312 and 962 keV and direct capture to the ground state. Asymptotic normalization coefficients (ANCs) for the ground and seven excited states in {sup 16}O were extracted from the comparison of experimental differential cross sections for the {sup 15}N({sup 3}He,d){sup 16}O reaction with distorted-wave Born approximation calculations. Using these ANCs and proton and {alpha} resonance widths determined from an R-matrix fit to the data from the {sup 15}N(p,{alpha}){sup 12}C reaction, we carried out an R-matrix calculation to obtain the astrophysical factor for the {sup 15}N(p,{gamma}){sup 16}O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0)=36.0{+-}6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200{+-}300 cycles of the main CN cycle one CN catalyst is lost due to this reaction.
- OSTI ID:
- 21192069
- Journal Information:
- Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 78; ISSN 0556-2813; ISSN PRVCAN
- Country of Publication:
- United States
- Language:
- English
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