Coincidence measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow /><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>12</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>C(α,γ<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>16</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>O cross section at

Kremer, Richard M.; Barnes, C. A.; Chang, Kang‐Tsung; Evans, H. C.; Filippone, B. W.; Hahn, K. H.; Mitchell, L.W.

doi:10.1103/physrevlett.60.1475

Cited by 107 publications

(89 citation statements)

References 19 publications

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“…1987) Previously (Barker 1971(Barker , 1987, simultaneous R-matrix fits were made to the El capture cross section to the 16 0 ground state, the 12C+()( p-and f-wave phase shifts, and the delayed ()( spectrum following 16N f3 decay. Additional data are now available on the El cross section Kremer et al 1988) and on the phase shifts (Plaga et al 1987); we therefore fit these new data using the same method as before.…”

Section: Fits To Datamentioning

confidence: 99%

“…This is speCialised to the case of 12C(a,y)160 0004-9506/91/040369$05.00 F. C. Barker and T. Kajino in Section 3, which also contains some comments on the formulae used in earlier fits to E2 data. Section 4 gives the results of fits based on the R-matrix formula to the recent El and E2 data, including the cascade transitions Kremer et al 1988). The 1 2 C+OC elastic scattering phase shifts measured recently (Plaga et al 1987) are also fitted.…”

Section: Introductionmentioning

confidence: 99%

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The 12C(a,g)16O Cross Section at Low Energies

Barker¹,

Kajino²

1991

Aust. J. Phys.

142

137

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An R-matrix formula for the cross section for radiative capture reactions is developed and applied to fit recently measured 12C(oc,y) 16 0 data, for both ground-state transitions and cascade transitions through the 6·92 and 7 ·12 MeV levels. The correct treatment of the channel contributions is significant for the E2 cascade transitions. Consistent fits of the cascade and ground-state data suggest a value of the channel radius larger than those previously used, and consequently a value of the low-energy astrophysical S-factor appreciably larger than that adopted recently.

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Section: Fits To Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The 12C(a,g)16O Cross Section at Low Energies

Barker¹,

Kajino²

1991

Aust. J. Phys.

142

137

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“…Right:Astrophysical S-factor for the 12 C(α,γ) 16 O reaction with Rmatrix calculations of the E1 component [3]. Experimental data are from [13,14,15,16,17,18,19]. The solid line is our best R-matrix fit using our deduced γ 2 α for the 7.12 MeV state and the dashed lines when using our upper and lower values for γ 2 α 1.3 and 1.5 MeV is due to the f-wave contribution which was not considered in the calculation as it is not contributing to the E1 component we are interested in.…”

Section: R-matrix Calculations and Resultsmentioning

confidence: 99%

New indirect study of the 12 C(α,γ) 16 O reaction via the 12 C( 7 Li,t) 16 O transfer reaction

Hammache¹,

Oulebsir²,

Roussel³

et al. 2013

Proceedings of XII International Symposium on Nuclei in the Cosmos — PoS(NIC XII)

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The radiative capture reaction 12 C(α, γ) 16 O plays a key role in stellar nucleosynthesis and evolution. However the cross section of this reaction at stellar energies remains highly uncertain despite various experimental studies. The extrapolation down to stellar energy (E cm ∼300 keV) of the measured cross sections at higher energies is made difficult by the overlap of various contributions of which some are badly known such as that of the 2 + (E x =6.92 MeV) and 1 − (E x =7.12 MeV) sub-threshold states of 16 O. Indeed, the α-reduced widths and so the α-spectroscopicfactors of these two sub-threshold states are spread over too-large a range of values. Accordingly, a new determination of these quantities through 12 C( 7 Li,t) 16 O transfer reaction measurements at two incident energies and a detailed DWBA analysis of the data was performed recently at Orsay. The measured and calculated differential cross sections are presented as well as the obtained spectroscopic factors and the α-reduced widths for the 2 + and 1 − sub-threshold states. The R-matrix calculations of the 12 C(α, γ) 16 O cross section using our obtained α-reduced widths for the two sub-threshold resonances are presented and discussed. 12th Symposium on Nuclei in the Cosmos

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“…The four levels consist of the sub-threshold state at Ex=6.92 MeV, the states at Ex=9.85 MeV and Ex=11.52 MeV and a higher 2 + background wich represent the tails of other higher-lying 2 + states. For the E1 component, the l=1 Rmatrix fitting was performed using a three 1 − levels including a background state, the phase shifts from [12] and the astrophysical S-factors data from [14,16,18,19] (see Figure 2, right ). The three levels consist of the subthreshold state at Ex=7.12 MeV, the state at Ex=9.585 MeV and a higher 1 − background state which illustrate the tails of other higher-lying 1 − states.…”

Section: Pos(nic Xi)129mentioning

confidence: 99%

Study of 12C(\alpha ,\gamma )16O reaction via the transfer reaction 12C(7Li,t)16O

Oulebsir¹,

Hammache²,

Roussel³

et al. 2011

Proceedings of 11th Symposium on Nuclei in the Cosmos — PoS(NIC XI)

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The 12 C(α, γ) 16 O reaction plays an important role in helium burning in massive stars and their evolution. However, despite many experimental studies, the low-energy cross section of 12 C(α, γ)16 O remains highly uncertain. The extrapolation of the measured cross sections to stellar energies (E=300 keV) is made difficult by the presence of the two sub-threshold states at 6.92 (2 + ) and 7.12 (1 − ) MeV of 16 O. In order to further investigate the contribution of these twosubthreshold resonances to the 12 C(α, γ) 16 O cross section, we performed a new determination of the α-reduced widths of the 6.92 and 7.12 MeV of 16 O via a measurement of the transfer reaction 12 C( 7 Li,t) 16 O at two incident energies, 34 and 28 MeV. The measured and calculated differential cross sections are presented as well as the obtained spectroscopic factors and the α-reduced widths for the 2 + and 1 − sub-threshold states and their effect on the R-matrix calculations of 12 C(α, γ) 16 O. 11th Symposium on Nuclei in the Cosmos

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Coincidence measurement of the12C(α,γ)16O cross section at

Cited by 107 publications

References 19 publications

The 12C(a,g)16O Cross Section at Low Energies

The 12C(a,g)16O Cross Section at Low Energies

New indirect study of the 12 C(α,γ) 16 O reaction via the 12 C( 7 Li,t) 16 O transfer reaction

Study of 12C(\alpha ,\gamma )16O reaction via the transfer reaction 12C(7Li,t)16O

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