Absolute cross sections measurement for the 12C + 12C system at astrophysically relevant energies

Barrón‐Palos, L.; Aguilera, E. F.; Aspiazu, J.; Huerta, A.; Martinez‐Quiroz, E.; Monroy, R.; Moreno, E.; Murillo, G.; Ortíz, María Esther; Policroniades, R.; Varela, A.; Chávez, E.

doi:10.1016/j.nuclphysa.2006.09.004

Cited by 91 publications

(91 citation statements)

References 26 publications

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“…The data show a rise in the S-factor at the lowest energies, which might indicate the existence of a broad resonance in the entrance channel, possibly related to an intermediate state in the compound nucleus [22]. Similar broad resonances in the S-factor at energies below the barrier have been also inferred from the 12 C+ 16 O total cross sections [23].…”

Section: Representations Of Low-energy Cross Sectionssupporting

confidence: 71%

Signature of shallow potentials in deep sub-barrier fusion reactions

2007

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We extend a recent study that explained the steep falloff in the fusion cross section at energies far below the Coulomb barrier for the symmetric dinuclear system 64 Ni+ 64 Ni to another symmetric system, 58 Ni+ 58 Ni, and the asymmetric system 64 Ni+ 100 Mo. In this scheme the very sensitive dependence of the internal part of the nuclear potential on the nuclear equation of state determines a reduction of the classically allowed region for overlapping configurations and consequently a decrease in the fusion cross sections at bombarding energies far below the barrier. Within the coupled-channels method, including couplings to the low-lying 2 + and 3 − states in both target and projectile as well as mutual and two-phonon excitations of these states, we calculate and compare with the experimental fusion cross sections, S-factors, and logarithmic derivatives for the above mentioned systems and find good agreement with the data even at the lowest energies. We predict, in particular, a distinct double peaking in the S-factor for the far subbarrier fusion of 58 Ni+ 58 Ni which should be tested experimentally.

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Section: Representations Of Low-energy Cross Sectionssupporting

confidence: 71%

Signature of shallow potentials in deep sub-barrier fusion reactions

2007

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“…Becker et al 1981). The rate from CF88 differs from that of FCZ75 by less than 20% at T 10 9 K, and by less than a factor 2.5 at T 10 8 K. In the past 30 years, the lower limit to E cm reached experimentally has decreased to only 2.10 MeV Barrón-Palos et al 2006;Spillane et al 2007), because of experimental difficulties in reducing the background related to secondary reactions induced by hydrogen and deuterium contamination in the carbon targets. Present-day data exhibit pronounced resonances throughout the measured energy range.…”

Section: Introductionmentioning

confidence: 95%

Type Ia supernovae and the¹²C+¹²C reaction rate

Bravo

Piersanti

Domínguez

et al. 2011

A&A

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Context. Even if the 12 C+ 12 C reaction plays a central role in the ignition of type Ia supernovae (SNIa), the experimental determination of its cross-section at astrophysically relevant energies (E 2 MeV) has never been made. The profusion of resonances throughout the measured energy range has led to speculation that there is an unknown resonance at E 0 ∼ 1.5 MeV possibly as strong as the one measured for the resonance at 2.14 MeV, i.e. (ωγ) R = 0.13 meV. Aims. We study the implications that such a resonance would have for our knowledge of the physics of SNIa, paying special attention to the phases that go from the crossing of the ignition curve to the dynamical event.Methods. We use one-dimensional hydrostatic and hydrodynamic codes to follow the evolution of accreting white dwarfs until they grow close to the Chandrasekhar mass and explode as SNIa. In our simulations, we account for a low-energy resonance by exploring the parameter space allowed by experimental data. Results. A change in the 12 C+ 12 C rate similar to the one explored here would have profound consequences for the physical conditions in the SNIa explosion, namely the central density, neutronization, thermal profile, mass of the convective core, location of the runaway hot spot, or time elapsed since crossing the ignition curve. For instance, with the largest resonance strength we use, the time elapsed since crossing the ignition curve to the supernova event is shorter by a factor ten than for models using the standard rate of 12 C+ 12 C, and the runaway temperature is reduced from ∼8.14 × 10 8 K to ∼4.26 × 10 8 K. On the other hand, a resonance at 1.5 MeV, with a strength ten thousand times smaller than the one measured at 2.14 MeV, but with an α/p yield ratio substantially different from 1 would have a sizeable impact on the degree of neutronization of matter during carbon simmering. Conclusions. A robust understanding of the links between SNIa properties and their progenitors will not be attained until the 12 C+ 12 C reaction rate is measured at energies ∼1.5 MeV.

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“…In recent years, there have been a number of efforts geared towards an accurate determination of the 12 C+ 12 C lowenergy cross section [8][9][10]. However, the astrophysical cross section has, perhaps, become even more uncertain most recently due to the observation of an extremely large resonance at 2.14 MeV by Spillane et al [10].…”

Section: The Isotope Fusion Projectmentioning

confidence: 99%

Constraining the¹²C+¹²C fusion cross section for astrophysics

Bucher

Fang

Tang

et al. 2015

EPJ Web of Conferences

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Abstract. The 12 C+ 12 C reaction is one of the single most important nuclear reactions in astrophysics. It strongly influences late evolution of massive stars as well as the dynamics of type Ia supernovae and x-ray superbursts. An accurate estimation of the cross section at relevant astrophysical energies is extremely important for modeling these systems. However, the situation is complicated by the unpredictable resonance structure observed at higher energies. Two recent studies at Notre Dame have produced results which help reduce the uncertainty associated with this reaction. The first uses correlations with the isotope fusion systems, 12 C+ 13 C and 13 C+ 13 C, to establish an upper limit on the resonance strengths in 12 C+ 12 C. The other focuses on the specific channel 12 C+ 12 C→ 23 Mg+n and its low-energy measurement and extrapolation which is relevant to s-process nucleosynthesis. The results from each provide important constraints for astrophysical models.

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Absolute cross sections measurement for the 12C + 12C system at astrophysically relevant energies

Cited by 91 publications

References 26 publications

Signature of shallow potentials in deep sub-barrier fusion reactions

Signature of shallow potentials in deep sub-barrier fusion reactions

Type Ia supernovae and the¹²C+¹²C reaction rate

Constraining the¹²C+¹²C fusion cross section for astrophysics

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Absolute cross sections measurement for the 12C + 12C system at astrophysically relevant energies

Cited by 91 publications

References 26 publications

Signature of shallow potentials in deep sub-barrier fusion reactions

Signature of shallow potentials in deep sub-barrier fusion reactions

Type Ia supernovae and the12C+12C reaction rate

Constraining the12C+12C fusion cross section for astrophysics

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Product

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Type Ia supernovae and the¹²C+¹²C reaction rate

Constraining the¹²C+¹²C fusion cross section for astrophysics