Probing astrophysically important states in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Mg</mml:mi><mml:mprescripts /><mml:none /><mml:mn>26</mml:mn></mml:mmultiscripts></mml:math>nucleus to study neutron sources for the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>process

Talwar, R.; Adachi, T.; Berg, G.P.A.; Bin, Liao; Bisterzo, S.; Couder, M.; deBoer, R. J.; Fang, X.; Fujita, H.; Fujita, Y.; Görres, J.; Hatanaka, K.; Itoh, Tadashi; Kadoya, T.; Long, Alexander; Miki, K.; Patel, D.; Pignatari, M.; Shimbara, Y.; Tamii, A.; Wiescher, M.; Yamamoto, Tetsuya; Yosoi, M.

doi:10.1103/physrevc.93.055803

Cited by 43 publications

(154 citation statements)

References 87 publications

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“…The γ-decaying resonance at E x = 11.171 MeV is the likely candidate for the strong α cluster state with J π = (1 − , 2 + ) reported by Talwar et al [6]. Our upper limit on the spectroscopic factor for this state is substantially below that reported in Ref.…”

Section: Resonances Below 1132 Mevcontrasting

confidence: 55%

“…[11,42]) is that the state observed in Ref. [6] is actually a higher-spin state (J ≥ 3) and thus more likely to be populated with their beam energy of E (lab) 6 Li = 82.3 MeV. This would also be consistent with a very recent GAMMASPHERE measurement which observed γ-ray decay from a state at E x = 11.171 MeV to a 4 + level, indicating a spin ranging from 2-6 [43].…”

Section: Resonances Below 1132 Mevmentioning

confidence: 91%

“…The presently-established (α, n) strength of this resonance results in a recommended rate that is up to a factor ∼3 lower than Refs. [5,6,21] in the crucial temperature regime from 0.2-0.4 GK. For T > 0.4 GK, resonances above E x = 11.32 MeV begin to contribute to the overall (α, n) rate, eventually becoming dominant for T > 0.6 GK.…”

Section: >1132mentioning

confidence: 99%

“…Despite extensive investigaton [5,6,, key properties of both the E x = 11.32 MeV resonance and lower-lying neutron-unbound resonances remain uncertain. In particular, the (α, n) strength of the E x = 11.32 MeV resonance is not well established, nor is its spin-parity.…”

Section: Introductionmentioning

confidence: 99%

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Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

et al. 2020

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The astrophysical s-process is one of the two main processes forming elements heavier than iron. A key outstanding uncertainty surrounding s-process nucleosynthesis is the neutron flux generated by the 22 Ne(α, n) 25 Mg reaction during the He-core and C-shell burning phases of massive stars. This reaction, as well as the competing 22 Ne(α, γ) 26 Mg reaction, is not well constrained in the important temperature regime from ∼0.2-0.4 GK, owing to uncertainties in the nuclear properties of resonances lying within the Gamow window. To address these uncertainties, we have performed a new measurement of the 22 Ne( 6 Li, d) 26 Mg reaction in inverse kinematics, detecting the outgoing deuterons and 25,26 Mg recoils in coincidence. We have established a new n/γ decay branching ratio of 1.14(26) for the key E x = 11.32 MeV resonance in 26 Mg, which results in a new (α, n) strength for this resonance of 42(11) µeV when combined with the well-established (α, γ) strength of this resonance. We have also determined new upper limits on the α partial widths of neutron-unbound resonances at E x = 11. 112, 11.163, 11.169, and 11.171 MeV. Monte-Carlo calculations of the stellar 22 Ne(α, n) 25 Mg and 22 Ne(α, γ) 26 Mg rates, which incorporate these results, indicate that both rates are substantially lower than previously thought in the temperature range from ∼0.2-0.4 GK.

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Section: Resonances Below 1132 Mevcontrasting

confidence: 55%

Section: Resonances Below 1132 Mevmentioning

confidence: 91%

Section: >1132mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

et al. 2020

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“…The two lines are similar, indicating that the difference in the actual CO core masses resulting from the different 12 C(α,γ) 16 O rates has no strong influence on the weak s-process element production, as for instance the α capture rates on the neutron source 22 Ne (e.g. see for a recent impact study Talwar et al (2015)). The weak s-process production is more efficient in the model that uses the adopted 12 C(α,γ) 16 O rate from this work because the rate is slower and therefore 12 C is 16 O rate of this work and that of Kunz et al (2002).…”

Section: Astrophysics Implicationsmentioning

confidence: 92%

The C12(α,γ)O16
deBoer
¹
,
Görres
²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
Self Cite
208
8
143
1
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The creation of carbon and oxygen in our universe is one of the forefront questions in nuclear astrophysics. The determination of the abundance of these elements is key to both our understanding of the formation of life on earth and to the life cycles of stars. While nearly all models of different nucleosynthesis environments are affected by the production of carbon and oxygen, a key ingredient, the precise determination of the reaction rate of 12 C(α, γ) 16 O, has long remained elusive. This is owed to the reaction's inaccessibility, both experimentally and theoretically. Nuclear theory has struggled to calculate this reaction rate because the cross section is produced through different underlying nuclear mechanisms. Isospin selection rules suppress the E1 component of the ground state cross section, creating a unique situation where the E1 and E2 contributions are of nearly equal amplitudes. Experimentally there have also been great challenges. Measurements have been pushed to the limits of state of the art techniques, often developed for just these measurements. The data have been plagued by uncharacterized uncertainties, often the result of the novel measurement techniques, that have made the different results challenging to reconcile. However, the situation has markedly improved in recent years, and the desired level of uncertainty, ≈10%, may be in sight. In this review the current understanding of this critical reaction is summarized. The emphasis is placed primarily on the experimental work and interpretation of the reaction data, but discussions of the theory and astrophysics are also pursued. The main goal is to summarize and clarify the current understanding of the reaction and then point the way forward to an improved determination of the reaction rate.

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Alpha-Capture Reaction Rate for $$^{22}$$ Ne( $$\alpha $$ , n) via Sub-Coulomb $$\alpha $$ -Transfer and Its Effect on Final Abundances of s-Process Isotopes

Jayatissa

Rogachev

Koshchiy

et al. 2019

Springer Proceedings in Physics

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Probing astrophysically important states in theMg26nucleus to study neutron sources for thesprocess

Cited by 43 publications

References 87 publications

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

The C12(α,γ)O16
deBoer
¹
,
Görres
²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
Self Cite
208
8
143
1
View full text Add to dashboard Cite

Alpha-Capture Reaction Rate for $$^{22}$$ Ne( $$\alpha $$ , n) via Sub-Coulomb $$\alpha $$ -Transfer and Its Effect on Final Abundances of s-Process Isotopes

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Probing astrophysically important states in theMg26nucleus to study neutron sources for thesprocess

Cited by 43 publications

References 87 publications

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

The C12(α,γ)O16deBoer1, Görres2, Wiescher3 et al. 2017Rev. Mod. Phys.Self Cite20881431View full textAdd to dashboardCite

Alpha-Capture Reaction Rate for $$^{22}$$ Ne( $$\alpha $$ , n) via Sub-Coulomb $$\alpha $$ -Transfer and Its Effect on Final Abundances of s-Process Isotopes

Contact Info

Product

Resources

About

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

Decay properties of 22Ne + α resonances and their impact on s-process nucleosynthesis

The C12(α,γ)O16
deBoer
¹
,
Görres
²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
Self Cite
208
8
143
1
View full text Add to dashboard Cite