Resonances above the proton threshold in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Si</mml:mi><mml:mprescripts /><mml:none /><mml:mn>26</mml:mn></mml:mmultiscripts></mml:math>

Chipps, K. A.

doi:10.1103/physrevc.93.035801

Cited by 11 publications

(16 citation statements)

References 42 publications

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“…Unfortunately, however, the gamma decay branch from this state, which has not been observed, sets the resonance strength. This radiative exit channel is expected to proceed primarily via emission of a gamma-ray of approximately 1740 keV [7][8][9] from the 3 + resonance state to the second 3 + state in 26 Si at 4187 keV [10]. Conveniently, even though direct measurements of proton capture to this 26 Si state are not yet possible, it is possible to exploit the relatively strong beta-decay population of the state from 26 P in order to study its properties [11].…”

Section: Introductionmentioning

confidence: 99%

Measurement of the Beta Decay of 26P to Determine Classical Nova 26Al Production in the Milky Way

Bennett

Wrede

Chipps

et al. 2015

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII)

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Observation across the Milky Way of a 1809-keV γ-ray characteristic of 26 Al decay provides direct evidence for ongoing nucleosynthetic production of 26 Al. Although massive stars and supernovae are likely to be the primary sites for 26 Al production, classical novae may also contribute a significant portion of the total amount of Galactic 26 Al. At peak nova temperatures of approximately 0.4 GK, the rate of the 25 Al(p,γ) 26 Si reaction, which bypasses 26 Al production and therefore places an upper limit on the amount of 26 Al contributed by novae to Galactic abundances, is likely dominated by a single 3 + resonance. Constraining the energy and strength of this resonance is therefore critical to determining the 25 Al(p,γ) 26 Si reaction rate. We have used a radioactive 26 P beam produced at the National Superconducting Cyclotron Laboratory to populate the 3 + state via beta decay, and have observed first evidence for its γ decay branch, the last piece of information needed to calculate the resonance strength. We find the 3 + state to have a resonance energy of E r = 414.9 ± 0.6 (stat) ± 0.3 (syst) ± 0.6 (lit.) keV and a resonance strength of ωγ = 23 ± 6 (stat) +11-10 (lit.) meV. We have also used hydrodynamic nova simulations to model 26 Al production and we find that novae may contribute up to 0.6 solar masses of the Galactic 26 Al-38% of the total Galactic 26 Al abundance.

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Section: Introductionmentioning

confidence: 99%

Measurement of the Beta Decay of 26P to Determine Classical Nova 26Al Production in the Milky Way

Bennett

Wrede

Chipps

et al. 2015

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII)

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“…Previous studies of the 25 Al(p, γ ) 26 Si reaction [5,[22][23][24][25][26][27][28][29][30][31][32][33] indicate that the rate is dominated by resonant capture to excited states in 26 Si above the proton-emission threshold energy of 5513.99 (13) keV [34]. Specifically, a 3 + 5927.6(10)-keV level in 26 Si, corresponding to a = 0 capture resonance on the 5/2 + ground state of 25 Al, is expected to make the most significant contribution.…”

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confidence: 99%

“…Consequently, the lifetime of the 3 + 6125-keV level in 26 Mg now represents one of the key remaining uncertainties in constraining the astrophysical 25 Al(p, γ ) 26 Si reaction rate. Furthermore, a study of the 25 Al(p, γ ) reaction by Chipps [23] has raised significant questions over the spin-parity assignment of a neighboring excited state in 26 Si at 5949.7 (53) keV. This level does not seem to match any of the evenparity levels in the mirror nucleus 26 Mg [38] or shell-model calculations [24] and, thus, may represent a previously unreported negative-parity resonance in the 25 Al(p, γ ) reaction.…”

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confidence: 99%

“…Consequently, we propose that the presently identified 5710-keV level in 26 Mg may only reasonably be assigned as the 1 − 1 excited state. For an evaluation of the 25 Al(p, γ ) stellar reaction rate, we consider the contribution of resonant states in 26 Si at 5675, 5890, 5928, and 5950 keV [23], respectively, (direct capture is expected to be negligible for temperature 0.1 GK). The recently reported isotropic angular distributions of γ decays from the 5890-keV level in 26 Si [28] indicate a good isobaric pairing with the 0 + 4 6256-keV excited state in 26 Mg, whereas the 1 + 1 5675-and 3 + 3 5928-keV states have already been previously well matched to analog states in 26 Mg at 5691 and 6125 keV [29], respectively.…”

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confidence: 99%

“…In contrast, the spin-parity assignment of the 5950-keV level in 26 Si remains somewhat controversial. In particular, Chipps [23] highlights specific difficulties with assigning this state either 0 + or 4 + 26 Mg. e Based on the known lifetime of the 1 − 7062-keV state in 26 Mg [38].…”

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confidence: 99%

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New constraints on the Al25(p,γ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions

et al. 2021

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Nuclear Data Sheets for A = 26

Basunia

Hurst

2016

Nuclear Data Sheets

111

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Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for 26 O, 26 F, 26 Ne, 26 Na, 26 Mg, 26 Al, 26 Si, 26 P, and 26 S. This evaluation for A=26 supersedes the earlier one by P. M. Endt (1998En04) and updates for some nuclides in ENSDF. Highlights of this evaluation are the following: This evaluation includes search results for 26 S nuclide and its proton-decay mode (2011Fo08). An isomeric state (2.2 ms) in 26 F has been discovered by 2013Le03. The state is proposed at 643.4 keV 1 from γ-ray measurements. Internal-transition and beta-decay branches for the state are also determined. New excited levels in 26 Ne have been identified from 26 F βdecay (2.2 ms). For some 26 Si resonance states conflicting spin-parity assignments exist in the literature. These are identified by footnotes. 2015Do07 (3 He,nγ) propose the first 0+ state above proton separation energy at an excitation energy of 5890 keV and suggested for additional independent measurements to confirm or refute the existence of 5946 keV 4. 2016Ch09 consider 5946 keV level as a distinct excited state in their reanalysis of the literature data with possible spin-parity assignment of 0+ or 4+ This evaluation also includes discovery of an isomeric state, at 164.1 keV 1, in 26 P by 2014NiZZ.

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Resonances above the proton threshold inSi26

Cited by 11 publications

References 42 publications

Measurement of the Beta Decay of 26P to Determine Classical Nova 26Al Production in the Milky Way

Measurement of the Beta Decay of 26P to Determine Classical Nova 26Al Production in the Milky Way

New constraints on the Al25(p,γ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions

Nuclear Data Sheets for A = 26

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