Neutron spectroscopy of 26Mg states: Constraining the stellar neutron source 22Ne(α,n)25Mg

Massimi, C.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Bisterzo, S.; Bosnar, D.; Brügger, M.; Calviani, M.; Calviño, F.; Cano‐Ott, D.; Carrapiço, C.; Castelluccio, Donato Maurizio; Cerutti, F.; Chiaveri, E.; Coséntino, L.; Chin, M.; Clai, G.; Colonna, N.; Cortés, G.; Cortés‐Giraldo, M. A.; Cristallo, S.; Diakaki, Μ.; Domingo‐Pardo, C.; Durán, I.; Dressler, R.; Eleftheriadis, C.; Ferrari, A.; Finocchiaro, P.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González‐Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Kopecky, S.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L.S.; Meo, S. Lo; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Mastinu, P.; Mastromarco, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Musumarra, A.; Paradela, C.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Piersanti, L.; Arjan, Plompen; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Taín, J. L.; Tarrío, D.; Tassan‐Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Rijs, I. Van; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wynants, R.; Wright, T.; Žugec, P.

doi:10.1016/j.physletb.2017.02.025

Cited by 36 publications

(96 citation statements)

References 16 publications

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“…To account for uncertainties in the peak energy, the centroid of each Gaussian was allowed to vary by ±10 keV from the nominal-with the exception of the peak at ∼11.17 MeV. Because multiple natural-parity states have been identified in the region around 11.17 MeV [21], and furthermore because of the controversy between Ref. [11] and Ref.…”

Section: 32 Mev Resonancementioning

confidence: 99%

“…In particular it disagrees by 5.0σ with the Table 2: Resonance parameters determined for the 26 Mg 11.32 MeV state and natural parity states between the neutron threshold and 11.25 MeV identified in Refs. [20,21]. All upper limits are quoted at 90% CL, and uncertainties in parentheses are quoted at 1σ (68% CL).…”

Section: 32 Mev Resonancementioning

confidence: 99%

“…Specifically, we use the amplitude of the ∼11.17 MeV peak in the 25 Mg-gated spectrum to set a 90% confidence level (CL) upper limit on the 22 Ne( 6 Li, dn) 25 Mg cross section for any one state between 11.17-11.25 MeV. We then use this cross section to calculate upper limits on the ( 6 Li, dn) cross section for each of the four natural-parity states identified in Ref [21] (E x = 11.112, 11.163,11.169,and 11.171 MeV). For this, we assume that 100% of the observed upper-limit strength goes into each state individually.…”

Section: Resonances Below 1132 Mevmentioning

confidence: 99%

“…Based on these results, the authors established that this state dominates the 22 Ne(α, γ) 26 Mg rate between ∼0.2-0.4 GK and that it could potentially dominate the 22 Ne(α, n) 25 Mg rate below 0.2 GK. More recently, neutron capture studies by Massimi et al have identified four natural-parity resonances in the 26 Mg excitation energy range from 11.1-11.3 MeV [20,21]. Three of these resonances were found to stongly neutron decay, while the fourth, E x = 11.171 MeV, was identified as a 2 + state with a significant γ-ray decay branch (Γ n /Γ γ = 0.2-6).…”

Section: Introductionmentioning

confidence: 99%

“…Taken in conjunction with the resonance parameters (J, Γ n , Γ γ ) established by Massimi et al, this results in new upper limits on both the (α, n) and (α, γ) strengths for the four natural-parity states in this region identified in Refs. [20,21].…”

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: 32 Mev Resonancementioning

confidence: 99%

Section: 32 Mev Resonancementioning

confidence: 99%

Section: Resonances Below 1132 Mevmentioning

confidence: 99%

Section: Introductionmentioning

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 Importance of the $$^{13}$$ C( $$\alpha $$ ,n) $$^{16}$$ O Reaction in Asymptotic Giant Branch Stars

Cristallo¹

2019

Springer Proceedings in Physics

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Low mass Asymptotic Giant Branch stars are among the most important polluters of the interstellar medium. In their interiors, the main component (A 90) of the slow neutron capture process (the s-process) is synthesized, the most important neutron source being the 13 C(α,n) 16 O reaction. In this paper we review its current experimental status, discussing possible future synergies between some experiments currently focused on the determination of its rate. Moreover, in order to determine the level of precision needed to fully characterize this reaction, we present a theoretical sensitivity study, carried out with the FUNS evolutionary stellar code and the NEWTON post-process code. We modify the rate up to a factor of two with respect to a reference case. We find that variations of the 13 C(α,n) 16 O rate do not appreciably affect s-process distributions for masses above 3 M ⊙ at any metallicity. Apart from a few isotopes, in fact, the differences are always below 5%. The situation is completely

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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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Neutron spectroscopy of 26Mg states: Constraining the stellar neutron source 22Ne(α,n)25Mg

Cited by 36 publications

References 16 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 Importance of the $$^{13}$$ C( $$\alpha $$ ,n) $$^{16}$$ O Reaction in Asymptotic Giant Branch Stars

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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Neutron spectroscopy of 26Mg states: Constraining the stellar neutron source 22Ne(α,n)25Mg

Cited by 36 publications

References 16 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 Importance of the $$^{13}$$ C( $$\alpha $$ ,n) $$^{16}$$ O Reaction in Asymptotic Giant Branch Stars

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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Product

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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