1. Low-energy fusion hindrance in medium-light systems.
- Author
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Montagnoli, Giovanna
- Subjects
- *
NUCLEAR fusion , *QUANTUM tunneling , *MANY-body problem , *NUCLEAR astrophysics , *PAULI exclusion principle - Abstract
Heavy-ion fusion reactions give fundamental information on the quantum tunnelling of many-body systems where several intrinsic degrees of freedom are contributing. Moreover, the existence of hindrance in the fusion of light systems is critical for a variety of stellar environments. Hindrance is often characterised by a maximum of the astrophysical S factor with decreasing energy, and is an interesting link between heavy-ion fusion and astrophysics. The underlying physical background is still under debate. Recently it has been pointed out that the Pauli exclusion principle influences the ion-ion potential and, as a consequence, low-energy fusion hindrance is produced because of the thicker and higher Coulomb barrier. We recently performed systematic investigations on the fusion of several medium-light systems to establish a reliable basis for the extrapolation to the lighter cases of astrophysical interest. The results obtained for 12C + 24,26Mg and 12C + 30Si are discussed here. Hindrance is observed in all cases, however, with differing features, so extrapolating to lighter systems is not straightforward. Additionally, oscillations are observed in the sub-barrier logarithmic slopes of the 12C + 24,26Mg excitation functions, which complicates identifying the hindrance threshold in those two cases. Coupled-channels calculations for all these systems have been performed. The results show that fusion cross sections are well reproduced by simple tunnelling through the potential barrier, at the lowest energies. An alternative way to represent the data is discussed, which helps identifying the various channel couplings. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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