6533b86efe1ef96bd12cb123

RESEARCH PRODUCT

New constraints on the Al 25 (p,γ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions

L. CaneteG. LotayG. ChristianD.t. DohertyW. N. CatfordS. HallamD. SeweryniakH. M. AlbersS. Almaraz-calderónE. Andrew BennettM. P. CarpenterC. J. ChiaraJ. P. GreeneC. R. HoffmanR. V. F. JanssensA. KankainenT. LauritsenA. MattaM. Moukaddam

subject

Nucleon induced nuclear reactionsRadiative captureNuclear astrophysicsNuclear reactionsLifetimes and widthsNuclear structure and decaysNucleosynthesis in explosive environments

description

The astrophysical Al25(p,γ)Si26 reaction represents one of the key remaining uncertainties in accurately modeling the abundance of radiogenic Al26 ejected from classical novae. Specifically, the strengths of key proton-unbound resonances in Si26, that govern the rate of the Al25(p,γ) reaction under explosive astrophysical conditions, remain unsettled. Here, we present a detailed spectroscopy study of the Si26 mirror nucleus Mg26. We have measured the lifetime of the 3+, 6.125-MeV state in Mg26 to be 19(3)fs and provide compelling evidence for the existence of a 1- state in the T=1,A=26 system, indicating a previously unaccounted for=1 resonance in the Al25(p,γ) reaction. Using the presently measured lifetime, together with the assumption that the likely 1- state corresponds to a resonance in the Al25+p system at 435.7(53) keV, we find considerable differences in the Al25(p,γ) reaction rate compared to previous works. Based on current nova models, we estimate that classical novae may be responsible for up to ≈15% of the observed galactic abundance of Al26.

yearjournalcountryeditionlanguage
2021-08-16
10.1103/physrevc.104.l022802http://hdl.handle.net/10261/261000