Abstract
Proton capture on the excited isomeric state of strongly influences the abundance of ejected in explosive astronomical events and, as such, plays a critical role in determining the initial content of radiogenic in presolar grains. This reaction also affects the temperature range for thermal equilibrium between the ground and isomeric levels. We present a novel technique, which exploits the isospin symmetry of the nuclear force, to address the long-standing challenge of determining proton-capture rates on excited nuclear levels. Such a technique has in-built tests that strongly support its veracity and, for the first time, we have experimentally constrained the strengths of resonances that dominate the astrophysical reaction. These constraints demonstrate that the rate is at least a factor lower than previously expected, indicating an increase in the stellar production of and a possible need to reinvestigate sensitivity studies involving the thermal equilibration of .
- Received 23 October 2020
- Revised 23 November 2020
- Accepted 12 January 2021
DOI:https://doi.org/10.1103/PhysRevLett.126.042701
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