Constraining the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>S</mml:mi></mml:mrow></mml:math>factor of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">N</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>15</mml:mn></mml:mrow></mml:mmultiscripts><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:mi>p</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo stretchy="false">)</mml:mo></mml

LeBlanc, P. J.; Imbriani, G.; Junker, M.; Azuma, R.E.; Beard, M.; Bemmerer, D.; Best, A.; Broggini, C.; Caciolli, A.; Corvisiero, P.; Costantini, H.; Couder, M.; deBoer, R. J.; Elekes, Z.; Falahat, S.; Formicola, A.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Käppeler, F.; Kontos, A.; Kuntz, R.; Leiste, H.; Lemut, A.; Li, Q.; Limata, B.; Marta, M.; Mazzocchi, C.; Menegazzo, R.; O’Brien, S.; Palumbo, A.; Prati, P.; Roca, V.; Rolfs, C.; Alvarez, C. Rossi; Somorjai, E.; Stech, E.; Straniero, O.; Strieder, F.; Tan, Wanpeng; Terrasi, F.; Trautvetter, H. P.; Uberseder, E.; Wiescher, M.

doi:10.1103/physrevc.82.055804

Cited by 40 publications

(56 citation statements)

References 31 publications

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“…However, the Coulomb interaction breaks isospin symmetry, causing the states to become isospin mixed, allowing for such transitions to take place, albeit at a reduced strength. This is the primary reason that the E1 and E2 multipolarity components of the 12 C(α, γ 0 ) Schürmann et al (2005), the 15 N(p, γ0) 16 O those of LeBlanc et al (2010), the 16 N(βα) 12 C spectrum is from Buchmann et al (1993), and the 12 C(α, α0) 12 C data are from Tischhauser et al (2002). The solid red curve represents the phenomenological R-matrix fit described in this work.…”

Section: Thementioning

confidence: 94%

“…The 15 N(p, γ) 16 O reaction has been the subject of several recent measurements at the LUNA facility and the University of Notre Dame's nuclear science laboratory (Bemmerer et al, 2009;Caciolli, A. et al, 2011;Imbriani et al, 2012;LeBlanc et al, 2010). This was highly motivated by new measurements of the bound state proton ANCs in 16 O (Mukhamedzhanov et al, 2008), which gave strong evidence that the measurement of Rolfs and Rodney (1974) over estimated the low energy cross section, a common theme.…”

Section: Return To Indirect Techniques ('93-present)mentioning

confidence: 99%

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

et al. 2017
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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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Section: Thementioning

confidence: 94%

Section: Return To Indirect Techniques ('93-present)mentioning

confidence: 99%

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

et al. 2017
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“…This measurement covered only the low-energy region, E 230 keV, where E is the relative 15 N − p energy. The second study of 15 N(p, γ ) 16 O, which was just reported in [21], was performed over a wide energy range at the Notre Dame Nuclear Science Laboratory (NSL) and the LUNA II facility. The obtained S(0) = 39.6 ± 2.6 keVb is in a perfect agreement with our prediction S(0) = 36.0 ± 6.0 keVb [13].…”

Section: Introductionmentioning

confidence: 99%

“…However, in the R-matrix fitting of the experimental data, the ANC was used as an unconstrained fitting parameter and the best fit with the normalizedχ 2 = 1.80 was achieved for the square of the ANC C 2 = 539 ± 138 fm −1 , which is significantly higher than our measured value C 2 = 192 ± 26 fm −1 . Significant deviation of the ANC obtained in [21] signals that some physical input is missing in the reaction model and this incomplete knowledge is compensated for by adopting an unphysical value of the ANC. In the case under consideration, in the R-matrix approach, the ANC determines the overall normalization of the nonresonant radiative capture amplitude and the channel (external) part of the radiative width amplitudes of both resonances involved.…”

Section: Introductionmentioning

confidence: 99%

AstrophysicalSfactor for theN15(p,

2011

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The R-matrix approach has proved to be very useful in extrapolating the astrophysical factor down to astrophysically relevant energies, since the majority of measurements are not available in this region. However, such an approach has to be critically considered when no complete knowledge of the reaction model is available. To get reliable results in such cases one has to use all the available information from independent sources and, accordingly, fix or constrain variations of the parameters. In this paper we present a thorough R-matrix analysis of the 15 N(p, γ ) 16 O reaction, which provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong J π = 1 − resonances at E R = 312 and 962 keV and direct capture to the ground state. Recently, a new measurement of the astrophysical factor for the 15 N(p, γ ) 16 O reaction has been published [P. J. LeBlanc et al., Phys. Rev. C 82, 055804 (2010)]. The analysis has been done using the R-matrix approach with unconstrained variation of all parameters including the asymptotic normalization coefficient (ANC). The best fit has been obtained for the square of the ANC C 2 = 539.2 fm −1 , which exceeds the previously measured value by a factor of ≈ 3. Here we present a new R-matrix analysis of the Notre Dame-LUNA data with the fixed within the experimental uncertainties square of the ANC C 2 = 200.34 fm −1 . Rather than varying the ANC we add the contribution from a background resonance that effectively takes into account contributions from higher levels. Altogether we present ten fits, seven unconstrained and three constrained. For the unconstrained fit with the boundary condition B c = S c (E 2 ), where E 2 is the energy of the second level, we get S(0) = 39.0 ± 1.1 keVb and normalizedχ 2 = 1.84, i.e., the result which is similar to LeBlanc et al. From all our fits we get the range 33.1 S(0) 40.1 keVb which overlaps with the result of LeBlanc et al. We address also the physical interpretation of the fitting parameters.

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“…Parameters that remain unconstrained by the data are fixed to those available in the literature. The quoted uncertainties for this work are of the form (statistical, systematic) where the statistical uncertainty arises from the counts of the yield data and the systematic uncertainty from the 5% absolute normalization of the cross sections [4]. Where the statistical uncertainty dominates, only one uncertainty is quoted.…”

mentioning

confidence: 99%

Erratum: Measurement ofγrays from15N(p,γ)
Imbriani¹,
deBoer²,
Best³
et al. 2012
Phys. Rev. C
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Constraining theSfactor ofN15(p,γ)

Cited by 40 publications

References 31 publications

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

et al. 2017
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The C12(α,γ)O16
deBoer
¹
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²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
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AstrophysicalSfactor for theN15(p,

Erratum: Measurement ofγrays from15N(p,γ)
Imbriani¹,
deBoer²,
Best³
et al. 2012
Phys. Rev. C
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12
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Constraining theSfactor ofN15(p,γ)

Cited by 40 publications

References 31 publications

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

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

AstrophysicalSfactor for theN15(p,

Erratum: Measurement ofγrays from15N(p,γ)Imbriani1, deBoer2, Best3 et al. 2012Phys. Rev. CSelf Cite123120View full textAdd to dashboardCite

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

et al. 2017
Rev. Mod. Phys.
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208
8
143
1
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The C12(α,γ)O16
deBoer
¹
,
Görres
²
,
Wiescher
³

et al. 2017
Rev. Mod. Phys.
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208
8
143
1
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Erratum: Measurement ofγrays from15N(p,γ)
Imbriani¹,
deBoer²,
Best³
et al. 2012
Phys. Rev. C
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12
3
12
0
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