Oscillations above the barrier in the fusion of 28Si + 28Si

Montagnoli, G.; Stefanini, A.; Esbensen, H.; Corradi, L.; Courtin, S.; Fioretto, E.; Grȩbosz, J.; Haas, F.; Jia, H. M.; Jiang, C. L.; Mazzocco, M.; Michelagnoli, C.; Mijatović, T.; Montanari, D.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Torresi, D.

doi:10.1016/j.physletb.2015.05.021

Cited by 15 publications

(26 citation statements)

References 27 publications

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“…12 C + 12 C, the cross sections show oscillations due to the reduced number of partial waves contributing to the fusion process [40,41]. This might affect the values of R and M 1 extracted from the data.…”

Section: E E Limitations and Future Improvementsmentioning

confidence: 99%

Moments of fusion-barrier distributions

et al. 2016

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Section: E E Limitations and Future Improvementsmentioning

confidence: 99%

Moments of fusion-barrier distributions

et al. 2016

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“…The calculations that include absorption do exhibit some structures at high energies. These structures can be associated with the individual centrifugal barriers that we discussed in previous works [12,14].…”

Section: Results Of Coupled-channels Calculationsmentioning

confidence: 68%

“…The problem was solved in Refs. [1,12] by applying an imaginary potential with a diffuseness of a w = 0.2 to 0.3 fm.…”

Section: Results Of Coupled-channels Calculationsmentioning

confidence: 99%

“…The proton + neutron densities were used to calculate the M3Y + repulsion potential [13]. [12] neutron density that is used to calculate the M3Y + repulsion double-folding potential. The proton density, on the other hand, is kept fixed with the radius R = 3.165 fm and the diffuseness a = 0.48 fm.…”

Section: Results Of Coupled-channels Calculationsmentioning

confidence: 99%

“…This was already performed for 28 Si + 28 Si in Refs. [1,12] and the following section shows the results of analogous calculations for 30 Si + 30 Si.…”

Section: Beamsmentioning

confidence: 99%

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Isotopic effects in sub-barrier fusion of Si + Si systems

et al. 2018

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Background: Recent measurements of fusion cross sections for the 28 Si + 28 Si system revealed a rather unsystematic behavior; i.e., they drop faster near the barrier than at lower energies. This was tentatively attributed to the large oblate deformation of 28 Si because coupled-channels (CC) calculations largely underestimate the 28 Si + 28 Si cross sections at low energies, unless a weak imaginary potential is applied, probably simulating the deformation. 30 Si has no permanent deformation and its low-energy excitations are of a vibrational nature. Previous measurements of this system reached only 4 mb, which is not sufficient to obtain information on effects that should show up at lower energies. Purpose: The aim of the present experiment was twofold: (i) to clarify the underlying fusion dynamics by measuring the symmetric case 30 Si + 30 Si in an energy range from around the Coulomb barrier to deep sub-barrier energies, and (ii) to compare the results with the behavior of 28 Si + 28 Si involving two deformed nuclei. Methods:30 Si beams from the XTU tandem accelerator of the Laboratori Nazionali di Legnaro of the Istituto Nazionale di Fisica Nucleare were used, bombarding thin metallic 30 Si targets (50 μg/cm 2 ) enriched to 99.64% in mass 30. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ERs) at very forward angles, and angular distributions of ERs were measured. Results: The excitation function of 30 Si + 30 Si was measured down to the level of a few microbarns. It has a regular shape, at variance with the unusual trend of 28 Si + 28 Si. The extracted logarithmic derivative does not reach the L CS limit at low energies, so that no maximum of the S factor shows up. CC calculations were performed including the low-lying 2 + and 3 − excitations. Conclusions: Using a Woods-Saxon potential the experimental cross sections at low energies are overpredicted, and this is a clear sign of hindrance, while the calculations performed with a M3Y + repulsion potential nicely fit the data at low energies, without the need of an imaginary potential. The comparison with the results for 28 Si + 28 Si strengthens the explanation of the oblate shape of 28 Si being the reason for the irregular behavior of that system.

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Semiempirical formula for fusion barriers of nuclei with 1 ≤ Z ≤ 20

Manjunatha

Sridhar²

2020

Indian J Phys

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Oscillations above the barrier in the fusion of 28Si + 28Si

Cited by 15 publications

References 27 publications

Moments of fusion-barrier distributions

Moments of fusion-barrier distributions

Isotopic effects in sub-barrier fusion of Si + Si systems

Semiempirical formula for fusion barriers of nuclei with 1 ≤ Z ≤ 20

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