Saved in:
| Main Author: | |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2411.03600 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866918071604609024 |
|---|---|
| author | Katsuma, M. |
| author_facet | Katsuma, M. |
| contents | The triple-$α$ reaction from the ternary continuum states at off-resonant energies, $α+α+α\rightarrow^{12}$C, remains an open question. This direct process is scrutinized using a non-adiabatic Faddeev hyperspherical harmonics $R$-matrix expansion method, and the derived reaction rates are discussed. After reviewing the model, the resultant photo-disintegration of $^{12}$C($2^+_1\rightarrow 0^+$) is shown to be much smaller than the values predicted by the adiabatic models for $0.15 \le E \le 0.35$ MeV. Despite the large difference, the derived reaction rates are illustrated to be concordant with the current evaluated rates for $0.08 \le T_9 \le 3$. The difference below $E=0.20$ MeV can be seen in the rates for $T_9 \le 0.07$. In comparison with the calculations, the rates are found to be reduced by a factor of 10$^{-4}$ at $T_9=0.05$, because of an accurate description for $^8$Be break-up. Uncertainties of the rates are also estimated by examining the sensitivity to the 3$α$ potentials. By introducing three-body $S$-factors and a resonant term, the present rates are expressed in an analytic form, and they are provided in a tabular form for astrophysical applications. To update the evaluated rates, non-resonant sequential process between $α+^8$Be could be removed. The astrophysical impact is not expected to be large, although the rates are reduced around $T_9=0.05$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_03600 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Triple-$α$ reaction rates below $T_9=3$ by a non-adiabatic three-body model Katsuma, M. Nuclear Theory Solar and Stellar Astrophysics The triple-$α$ reaction from the ternary continuum states at off-resonant energies, $α+α+α\rightarrow^{12}$C, remains an open question. This direct process is scrutinized using a non-adiabatic Faddeev hyperspherical harmonics $R$-matrix expansion method, and the derived reaction rates are discussed. After reviewing the model, the resultant photo-disintegration of $^{12}$C($2^+_1\rightarrow 0^+$) is shown to be much smaller than the values predicted by the adiabatic models for $0.15 \le E \le 0.35$ MeV. Despite the large difference, the derived reaction rates are illustrated to be concordant with the current evaluated rates for $0.08 \le T_9 \le 3$. The difference below $E=0.20$ MeV can be seen in the rates for $T_9 \le 0.07$. In comparison with the calculations, the rates are found to be reduced by a factor of 10$^{-4}$ at $T_9=0.05$, because of an accurate description for $^8$Be break-up. Uncertainties of the rates are also estimated by examining the sensitivity to the 3$α$ potentials. By introducing three-body $S$-factors and a resonant term, the present rates are expressed in an analytic form, and they are provided in a tabular form for astrophysical applications. To update the evaluated rates, non-resonant sequential process between $α+^8$Be could be removed. The astrophysical impact is not expected to be large, although the rates are reduced around $T_9=0.05$. |
| title | Triple-$α$ reaction rates below $T_9=3$ by a non-adiabatic three-body model |
| topic | Nuclear Theory Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2411.03600 |