Constraining the <sup>30</sup>P(p,γ)<sup>31</sup>S reaction rate via <sup>31</sup>Cl β-delayed proton decay and its effect on ONe nova nucleosynthesis
ORAL
Abstract
The 30P(p,γ)31S reaction rate plays a crucial role in understanding the nucleosynthesis of oxygen-neon (ONe) novae. This thermonuclear rate influences the isotopic and chemical abundances of nova ejecta, and constraing this reaction rate could help identify candidate presolar nova grains as well as provide more accurate calibrations for nova thermometers. The reaction proceeds primarily via proton capture into narrow, isolated resonance states lying just above the proton-separation energy in 31S. By determining the strength of a recently observed low-energy, Jπ = 3/2+ resonance, we can substantially reduce the nuclear uncertainties associated with modeling explosive nucleosynthesis in novae. Here we report the results of a 31Cl β-delayed proton decay experiment in which we meausred the very weak proton decay branch of this potentially dominant resonance. This represents the weakest β+-delayed particle emission ever measured for resonances below 400 keV. Using our experimentally determined proton branching ratio as well as available information in literature, we calculated the new total thermonuclear rate for 30P(p,γ)31S and interpret its astrophysical impact with fully hydrodynamic 1D nova simulations.
*We acknowledge funding support from the National Science Foundation under Grants No. PHY-1913554, No. PHY-1102511, No. PHY-1565546, No. PHY-1811855, No. PHY-2011890; the Department of Energy Office of Science under Award No. DE-SC0016052; the Natural Sciences and Engineering Research Council of Canada (NSERC); the Spanish MINECO grant AYA2017-86274-P, the E. U. FEDER funds, the AGAUR/Generalitat de Catalunya grant SGR-661/2017, and the EU Horizon 2020 grant 101008324 ChETEC-INFRA. This article also benefited from discussions within the "ChETEC" COST Action (CA16117). Additional funding sources include Korean NRF grant Nos. 2020R1A2C1005981 and 2016R1A5A1013277.
–
Publication:Submitted to Physical Review Letters on June 23, 2021
