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Title: Spin assignments for $$^{23}\hbox {Mg}$$ levels and the astrophysical $$^{22}\hbox {Na}(p,\gamma )^{23}\hbox {Mg}$$ reaction
Award ID(s):
1713857 1812316
Author(s) / Creator(s):
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Date Published:
Journal Name:
The European Physical Journal A
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Abstract

    The23Na(α,p)26Mg reaction has been identified as having a significant impact on the nucleosynthesis of several nuclei between Ne and Ti in Type Ia supernovae, and of23Na and26Al in massive stars. The reaction has been subjected to renewed experimental interest recently, motivated by high uncertainties in early experimental data and in the statistical Hauser-Feshbach models used in reaction rate compilations. Early experiments were affected by target deterioration issues and unquantifiable uncertainties. Three new independent measurements instead are utilizing inverse kinematics and Rutherford scattering monitoring to resolve this. In this work we present directly measured angular distributions of the emitted protons to eliminate a discrepancy in the assumptions made in the recent reaction rate measurements, which results in cross sections differing by a factor of 3. We derive a new combined experimental reaction rate for the23Na(α,p)26Mg reaction with a total uncertainty of 30% at relevant temperatures. Using our new23Na(α,p)26Mg rate, the26Al and23Na production uncertainty is reduced to within 8%. In comparison, using the factor of 10 uncertainty previously recommended by the rate compilation STARLIB,26Al and23Na production was changing by more than a factor of 2. In Type Ia supernova conditions, the impact on production of23Na is constrained to within 15%.

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