First Accurate Normalization of the β-delayed α Decay of 16N and Implications for the 12C(α,γ)16O Astrophysical Reaction Rate

Harkness-Brennan, LJ, Page, Robert and Judson, Daniel (2018) First Accurate Normalization of the β-delayed α Decay of 16N and Implications for the 12C(α,γ)16O Astrophysical Reaction Rate. Physical Review Letters, 121 (14). 142701-.

Access the full-text of this item by clicking on the Open Access link.

	Text IS605_PRL_submitted.pdf - Author Accepted Manuscript Available under License : See the attached licence file. Download (243kB)
	Text 1804.02040v1.pdf - Submitted version Available under License : See the attached licence file. Download (243kB)

Abstract

The ^{12}C(α,γ)^{16}O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ_{11}, of the bound 1^{-} level in ^{16}O is particularly important to determine the cross section. The magnitude of γ_{11} is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of ^{16}N, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1^{-} level [b_{β,11}=(5.02±0.10)×10^{-2}] and for β-delayed α emission [b_{βα}=(1.59±0.06)×10^{-5}]. Our value for b_{βα} is 33% larger than previously held, leading to a substantial increase in γ_{11}. Our revised value for γ_{11} is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ_{11}, which provides significantly improved constraints on the ^{12}C(α,γ) cross section in the energy range relevant to hydrostatic He burning.

Item Type:	Article
Additional Information:	6 pages, 5 figures
Uncontrolled Keywords:	beta decay, H & He burning, lifetimes and widths, nuclear structure and decays
Depositing User:	Symplectic Admin
Date Deposited:	21 Jan 2019 10:09
Last Modified:	19 Jan 2023 01:06
DOI:	10.1103/PhysRevLett.121.142701
Open Access URL:	https://doi.org/10.1103/PhysRevLett.121.142701
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3031393

Available Versions of this Item

• First Accurate Normalization of the β-delayed α Decay of 16N and Implications for the 12C(α,γ)16O Astrophysical Reaction Rate. (deposited 25 Oct 2018 08:19)
  • First Accurate Normalization of the β-delayed α Decay of 16N and Implications for the 12C(α,γ)16O Astrophysical Reaction Rate. (deposited 21 Jan 2019 10:09) [Currently Displayed]