Abstract
The efficiency of the slow neutron-capture process in massive stars is strongly influenced by neutron-capture reactions on light elements. At low metallicity, is an important neutron absorber, but the effectiveness of as a light-element neutron poison is modified by competition between subsequent and reactions. The strengths of key resonances within the Gamow window for core helium burning in massive stars are not well constrained by experiment. This work presents more precise measurements of resonances in the energy range keV. We extract resonance strengths of , , , and , for resonances at , 721, 814, and 1318 keV, respectively. We also report an upper limit for the 612 keV resonance of neV ( c.l.), which effectively rules out any significant contribution from this resonance to the reaction rate. From this work, a new thermonuclear reaction rate is calculated and compared to the literature. The effect of present uncertainties in the reaction rate on weak -process yields are then explored using postprocessing calculations based on a rotating low-metallicity massive star. The resulting reaction rate is lower with respect to the preexisting literature and found to enhance weak -process yields in rotating massive star models.
- Received 18 January 2022
- Accepted 6 June 2022
DOI:https://doi.org/10.1103/PhysRevC.105.065805
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