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β+Gamow-Teller Transition Strengths fromTi46and Stellar Electron-Capture Rates
- Source :
- Physical Review Letters. 112
- Publication Year :
- 2014
- Publisher :
- American Physical Society (APS), 2014.
-
Abstract
- The Gamow-Teller strength in the β(+) direction to (46)Sc was extracted via the (46)Ti(t,(3)He + γ) reaction at 115 MeV/u. The γ-ray coincidences served to precisely measure the very weak Gamow-Teller transition to a final state at 991 keV. Although this transition is weak, it is crucial for accurately estimating electron-capture rates in astrophysical scenarios with relatively low stellar densities and temperatures, such as presupernova stellar evolution. Shell-model calculations with different effective interactions in the pf shell-model space do not reproduce the experimental Gamow-Teller strengths, which is likely due to sd-shell admixtures. Calculations in the quasiparticle random phase approximation that are often used in astrophysical simulations also fail to reproduce the experimental Gamow-Teller strength distribution, leading to strongly overestimated electron-capture rates. Because reliable theoretical predictions of Gamow-Teller strengths are important for providing astrophysical electron-capture reaction rates for a broad set of nuclei in the lower pf shell, we conclude that further theoretical improvements are required to match astrophysical needs.
Details
- ISSN :
- 10797114 and 00319007
- Volume :
- 112
- Database :
- OpenAIRE
- Journal :
- Physical Review Letters
- Accession number :
- edsair.doi...........da2b4b05fa199089e646428d83be4635