Indirect study of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>12</mml:mn></mml:msup></mml:math>C(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>16</mml:mn></mml:msup></mml:math>O reac

Oulebsir, N.; Hammache, F.; Roussel, Pierre; Pellegriti, M. G.; Audouin, L.; Beaumel, D.; Bouda, A.; Descouvemont, Pierre; Fortier, S.; Gaudefroy, L.; Kiener, J.; Lefebvre‐Schuhl, A.; Tatischeff, V.

doi:10.1103/physrevc.85.035804

Cited by 63 publications

(82 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The primordial nucleosynthesis of light elements, D, 3,4 He and 7 Li, is one of the three observational pillars of the Big-Bang model. The observed primordial abundances for D and 3,4 He agree well with the predictions of BBN model together with the precise WMAP cosmic baryon density while 7 Li abundance observations in metal poor halo stars are three times smaller than BBN+WMAP predictions [7].…”

Section: The 7 LI Cosmological Problemmentioning

confidence: 99%

“…The details of the R-matrix calculations and the fitting procedure of the E2 and E1 measured phase shifts and astrophysical S-factors is given in [3]. The deduced S-factors at 300 keV for the E2 and E1 components, 50±19 keV-b and 100±28 keV respectively, were found in excellent agreement with those deduced in the ANC experiment of Brune et al [4] where the alpha-reduced widths of the two sub-threshold states were also fixed in the R-matrix fitting procedure.…”

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

“…In view of the large uncertainties surrounding the alpha-spectroscopic factors of the two sub-threshold states, a new measurement of these parameters was performed through the α transfer reaction 12 C( 7 Li,t)) 16 O [3].…”

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

“…The experiment [3] was performed at the Alto facility of Orsay using the magnetic Split-Pole spectrometer. A 7 Li beam was sent on a self-supporting enriched 12 C target.…”

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

See 3 more Smart Citations

Indirect techniques for astrophysical reaction rates determinations

Hammache¹,

Oulebsir²,

Benamara³

et al. 2016

EPJ Web of Conferences

Self Cite

View full text Add to dashboard Cite

Direct measurements of nuclear reactions of astrophysical interest can be challenging. Alternative experimental techniques such as transfer reactions and inelastic scattering reactions offer the possibility to study these reactions by using stable beams. In this context, I will present recent results that were obtained in Orsay using indirect techniques. The examples will concern various astrophysical sites, from the Big-Bang nucleosynthesis to the production of radioisotopes in massive stars.The main characteristics of the nuclear reactions involved in stellar nucleosynthesis is the low energy where they generally occur, between few keV to few MeV and at these energies the cross sections of these reactions are very small ranging from fbarn to hundreds of pbarn especially when it involves charged particles. This makes the direct measurements at stellar energies very difficult and often impossible. Hence direct measurement are usually performed at higher energies and then extrapolated down to stellar energies where the reactions occur. However the extrapolations can lead sometimes to wrong results when a possible very low energy resonance or the tail of a possible sub-threshold resonance are not taken into account. 201, 0 0 EPJ Web of Conferences

show abstract

Section: The 7 LI Cosmological Problemmentioning

confidence: 99%

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

“…The experiment [3] was performed at the Alto facility of Orsay using the magnetic Split-Pole spectrometer. A 7 Li beam was sent on a self-supporting enriched 12 C target.…”

Section: O Through α-Transfer Reactionmentioning

confidence: 99%

See 2 more Smart Citations

Indirect techniques for astrophysical reaction rates determinations

Hammache¹,

Oulebsir²,

Benamara³

et al. 2016

EPJ Web of Conferences

Self Cite

View full text Add to dashboard Cite

show abstract

“…The HF calculations were performed by considering the triton from ( 7 Li,t) as coming from evaporation of the compound nucleus 19 F and they were normalized by a factor extracted from the ratio of the absolute values of the compound nucleus cross sections calculated for the observed non-natural parity 1 − (8.87 MeV) state to those measured in this experiment [15].…”

Section: Pos(enas 6)034mentioning

confidence: 99%

Transfer reactions as a tool for nuclear astrophysics

Hammache¹

2013

Proceedings of VI European Summer School on Experimental Nuclear Astrophysics — PoS(ENAS 6)

View full text Add to dashboard Cite

The cross section of the nuclear reactions involved in stellar nucleosynthesis are often very difficult to measure directly at stellar energies because of their very low value and/or the radiaoctive nature of the concerned isotopes, often far from the valley of stability. Moreover, this situation can be complicated by the existence of very low energy resonances and/or subthreshold resonances. Indirect methods such as transfer reactions and the ANC method offer the possibility to overcome these difficulties. In this context, the transfer reaction method will be presented and then illustrated through the study of two cases, a resonant reaction case, 12 C(α,γ) 16 O and a direct (n,γ) capture case, 60 Fe(n,γ) 61 Fe

show abstract

Weak Interference Between the 1 $$^-$$ States in the Vicinity of $$\alpha $$ -Particle Threshold of $$^{16}$$ O

Katsuma

2019

Springer Proceedings in Physics

View full text Add to dashboard Cite

The subthreshold 1 − 1 state at an excitation energy Ex = 7.12 MeV in 16 O has been believed to enhance the S-factor of 12 C(α,γ) 16 O. The enhancement seems to originate from strong interference between 1 − 1 and 1 − 2 (Ex ≈ 9.6 MeV) in the vicinity of the α-particle threshold. However, weak interference between them and a resulting small E1 Sfactor are exemplified with R-matrix theory. Including a higher-order correction of the resonance parameters, the present example appears to reproduce the experimental data consistently. It would therefore be possible that the E1 S-factor is reduced at low energies.

show abstract

Indirect study of the12C(α,γ)16O reac

Cited by 63 publications

References 37 publications

Indirect techniques for astrophysical reaction rates determinations

Indirect techniques for astrophysical reaction rates determinations

Transfer reactions as a tool for nuclear astrophysics

Weak Interference Between the 1 $$^-$$ States in the Vicinity of $$\alpha $$ -Particle Threshold of $$^{16}$$ O

Contact Info

Product

Resources

About