Low-energy 23Al β-delayed proton decay and 22Na destruction in novae

• Published in: Physical review. C 2020-05, Vol.101 (5)
• Main Authors: Friedman, M., Budner, T., Pérez-Loureiro, D., Pollacco, E., Wrede, C., José, J., Brown, B. A., Cortesi, M., Fry, C., Glassman, B., Heideman, J., Janasik, M., Roosa, M., Stomps, J., Surbrook, J., Tiwari, P.
• Format: Article
• Language: English
• Subjects: Beta decay; cosmic ray composition & spectra; cosmic ray sources; explosive burning; gamma ray astronomy; nuclear astrophysics; NUCLEAR PHYSICS AND RADIATION PHYSICS; nuclear physics of explosive environments; nuclear reactions; nucleon induced nuclear reactions; proton emission; resonance reactions
• ISSN: 2469-9985; 2469-9993

The radionuclide 22Na is a target of γ-ray astronomy searches, predicted to be produced during thermonuclear runaways driving classical novae. The 22Na (p, γ) 23Mg reaction is the main destruction channel of 22Na during a nova, hence, its rate is needed to accurately predict the 22Na yield. However, experimental determinations of the resonance strengths have led to inconsistent results. In this Rapid Communication, we report a measurement of the branching ratios of the 23Al β-delayed protons as a probe of the key 204-keV (center-of-mass) 22Na (p, γ) 23Mg resonance strength. We report a factor of 5 lower branching ratio compared to the most recent literature value. The variation in 22Na yield due to nuclear data inconsistencies was assessed using a series of hydrodynamic nova outburst simulations and has increased to a factor of 3.8, corresponding to a factor of ≈ 2 uncertainty in the maximum detectability distance. Finally, this is the first reported scientific measurement using the Gaseous Detector with Germanium Tagging system.